Merge branch 'develop' of github.com:matrix-org/matrix-react-sdk into t3chguy/fix/18096

 Conflicts:

	src/components/structures/SpaceRoomView.tsx

	src/components/views/spaces/SpaceCreateMenu.tsx

	src/i18n/strings/en_EN.json

res/css/_components.scss

@@ -75,6 +75,7 @@
 @import "./views/dialogs/_CreateCommunityPrototypeDialog.scss";
 @import "./views/dialogs/_CreateGroupDialog.scss";
 @import "./views/dialogs/_CreateRoomDialog.scss";
+@import "./views/dialogs/_CreateSubspaceDialog.scss";
 @import "./views/dialogs/_DeactivateAccountDialog.scss";
 @import "./views/dialogs/_DevtoolsDialog.scss";
 @import "./views/dialogs/_EditCommunityPrototypeDialog.scss";
@@ -85,6 +86,7 @@
 @import "./views/dialogs/_HostSignupDialog.scss";
 @import "./views/dialogs/_IncomingSasDialog.scss";
 @import "./views/dialogs/_InviteDialog.scss";
+@import "./views/dialogs/_JoinRuleDropdown.scss";
 @import "./views/dialogs/_KeyboardShortcutsDialog.scss";
 @import "./views/dialogs/_ManageRestrictedJoinRuleDialog.scss";
 @import "./views/dialogs/_MessageEditHistoryDialog.scss";

res/css/views/context_menus/_IconizedContextMenu.scss

@@ -99,6 +99,10 @@ limitations under the License.
             .mx_IconizedContextMenu_icon + .mx_IconizedContextMenu_label {
                 padding-left: 14px;
             }
+
+            .mx_BetaCard_betaPill {
+                margin-left: 16px;
+            }
         }
     }
 

res/css/views/dialogs/_AddExistingToSpaceDialog.scss

@@ -54,11 +54,16 @@ limitations under the License.
             display: flex;
             margin-top: 12px;
 
-            // we can't target .mx_BaseAvatar here as it'll break the decorated avatar styling
+            .mx_DecoratedRoomAvatar, // we can't target .mx_BaseAvatar here as it'll break the decorated avatar styling
-            .mx_DecoratedRoomAvatar {
+            .mx_BaseAvatar.mx_RoomAvatar_isSpaceRoom {
                 margin-right: 12px;
             }
 
+            img.mx_RoomAvatar_isSpaceRoom,
+            .mx_RoomAvatar_isSpaceRoom img {
+                border-radius: 8px;
+            }
+
             .mx_AddExistingToSpace_entry_name {
                 font-size: $font-15px;
                 line-height: 30px;
@@ -73,41 +78,12 @@ limitations under the License.
                 align-items: center;
             }
         }
-    }
-
-    .mx_AddExistingToSpace_section_spaces {
-        .mx_BaseAvatar {
-            margin-right: 12px;
-        }
-
-        .mx_BaseAvatar_image {
-            border-radius: 8px;
-        }
-    }
-
-    .mx_AddExistingToSpace_section_experimental {
-        position: relative;
-        border-radius: 8px;
-        margin: 12px 0;
-        padding: 8px 8px 8px 42px;
-        background-color: $header-panel-bg-color;
 
+        .mx_AccessibleButton_kind_link {
             font-size: $font-12px;
             line-height: $font-15px;
-        color: $secondary-fg-color;
+            margin-top: 8px;
-
+            padding: 0;
-        &::before {
-            content: '';
-            position: absolute;
-            left: 10px;
-            top: calc(50% - 8px); // vertical centering
-            height: 16px;
-            width: 16px;
-            background-color: $secondary-fg-color;
-            mask-repeat: no-repeat;
-            mask-size: contain;
-            mask-image: url('$(res)/img/element-icons/room/room-summary.svg');
-            mask-position: center;
         }
     }
 
@@ -205,7 +181,12 @@ limitations under the License.
     min-height: 0;
     height: 80vh;
 
-    .mx_Dialog_title {
+    .mx_AddExistingToSpace {
+        display: contents;
+    }
+}
+
+.mx_SubspaceSelector {
     display: flex;
 
     .mx_BaseAvatar_image {
@@ -227,12 +208,6 @@ limitations under the License.
             line-height: $font-22px;
             margin: 0;
         }
-
-            .mx_AddExistingToSpaceDialog_onlySpace {
-                color: $secondary-fg-color;
-                font-size: $font-15px;
-                line-height: $font-24px;
-            }
     }
 
     .mx_Dropdown_input {
@@ -252,7 +227,7 @@ limitations under the License.
         }
 
         .mx_Dropdown_menu {
-                .mx_AddExistingToSpaceDialog_dropdownOptionActive {
+            .mx_SubspaceSelector_dropdownOptionActive {
                 color: $accent-color;
                 padding-right: 32px;
                 position: relative;
@@ -273,9 +248,10 @@ limitations under the License.
             }
         }
     }
-    }
 
-    .mx_AddExistingToSpace {
+    .mx_SubspaceSelector_onlySpace {
-        display: contents;
+        color: $secondary-fg-color;
+        font-size: $font-15px;
+        line-height: $font-24px;
     }
 }

res/css/views/dialogs/_CreateRoomDialog.scss

@@ -109,56 +109,4 @@ limitations under the License.
         margin: 0 85px 0 0;
         font-size: $font-12px;
     }
-
-    .mx_Dropdown {
-        margin-bottom: 8px;
-        font-weight: normal;
-        font-family: $font-family;
-        font-size: $font-14px;
-        color: $primary-fg-color;
-
-        .mx_Dropdown_input {
-            border: 1px solid $input-border-color;
 }
-
-        .mx_Dropdown_option {
-            font-size: $font-14px;
-            line-height: $font-32px;
-            height: 32px;
-            min-height: 32px;
-
-            > div {
-                padding-left: 30px;
-                position: relative;
-
-                &::before {
-                    content: "";
-                    position: absolute;
-                    height: 16px;
-                    width: 16px;
-                    left: 6px;
-                    top: 8px;
-                    mask-repeat: no-repeat;
-                    mask-position: center;
-                    background-color: $secondary-fg-color;
-                }
-            }
-        }
-
-        .mx_CreateRoomDialog_dropdown_invite::before {
-            mask-image: url('$(res)/img/element-icons/lock.svg');
-            mask-size: contain;
-        }
-
-        .mx_CreateRoomDialog_dropdown_public::before {
-            mask-image: url('$(res)/img/globe.svg');
-            mask-size: 12px;
-        }
-
-        .mx_CreateRoomDialog_dropdown_restricted::before {
-            mask-image: url('$(res)/img/element-icons/community-members.svg');
-            mask-size: contain;
-        }
-    }
-}
-

res/css/views/dialogs/_CreateSubspaceDialog.scss

@@ -0,0 +1,81 @@
+/*
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+.mx_CreateSubspaceDialog_wrapper {
+    .mx_Dialog {
+        display: flex;
+        flex-direction: column;
+    }
+}
+
+.mx_CreateSubspaceDialog {
+    width: 480px;
+    color: $primary-fg-color;
+    display: flex;
+    flex-direction: column;
+    flex-wrap: nowrap;
+    min-height: 0;
+
+    .mx_CreateSubspaceDialog_content {
+        flex-grow: 1;
+
+        .mx_CreateSubspaceDialog_betaNotice {
+            padding: 12px 16px;
+            border-radius: 8px;
+            background-color: $header-panel-bg-color;
+
+            .mx_BetaCard_betaPill {
+                margin-right: 8px;
+                vertical-align: middle;
+            }
+        }
+
+        .mx_JoinRuleDropdown + p {
+            color: $muted-fg-color;
+            font-size: $font-12px;
+        }
+    }
+
+    .mx_CreateSubspaceDialog_footer {
+        display: flex;
+        margin-top: 20px;
+
+        .mx_CreateSubspaceDialog_footer_prompt {
+            flex-grow: 1;
+            font-size: $font-12px;
+            line-height: $font-15px;
+            color: $secondary-fg-color;
+
+            > * {
+                vertical-align: middle;
+            }
+        }
+
+        .mx_AccessibleButton {
+            display: inline-block;
+            align-self: center;
+        }
+
+        .mx_AccessibleButton_kind_primary {
+            margin-left: 16px;
+            padding: 8px 36px;
+        }
+
+        .mx_AccessibleButton_kind_link {
+            padding: 0;
+        }
+    }
+}

res/css/views/dialogs/_JoinRuleDropdown.scss

@@ -0,0 +1,67 @@
+/*
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+.mx_JoinRuleDropdown {
+    margin-bottom: 8px;
+    font-weight: normal;
+    font-family: $font-family;
+    font-size: $font-14px;
+    color: $primary-fg-color;
+
+    .mx_Dropdown_input {
+        border: 1px solid $input-border-color;
+    }
+
+    .mx_Dropdown_option {
+        font-size: $font-14px;
+        line-height: $font-32px;
+        height: 32px;
+        min-height: 32px;
+
+        > div {
+            padding-left: 30px;
+            position: relative;
+
+            &::before {
+                content: "";
+                position: absolute;
+                height: 16px;
+                width: 16px;
+                left: 6px;
+                top: 8px;
+                mask-repeat: no-repeat;
+                mask-position: center;
+                background-color: $secondary-fg-color;
+            }
+        }
+    }
+
+    .mx_JoinRuleDropdown_invite::before {
+        mask-image: url('$(res)/img/element-icons/lock.svg');
+        mask-size: contain;
+    }
+
+    .mx_JoinRuleDropdown_public::before {
+        mask-image: url('$(res)/img/globe.svg');
+        mask-size: 12px;
+    }
+
+    .mx_JoinRuleDropdown_restricted::before {
+        mask-image: url('$(res)/img/element-icons/community-members.svg');
+        mask-size: contain;
+    }
+}
+

res/css/views/messages/_ViewSourceEvent.scss

@@ -43,8 +43,10 @@ limitations under the License.
         margin-bottom: 7px;
         mask-image: url('$(res)/img/feather-customised/minimise.svg');
     }
+}
 
-    &:hover .mx_ViewSourceEvent_toggle {
+.mx_EventTile:hover {
+    .mx_ViewSourceEvent_toggle {
         visibility: visible;
     }
 }

res/css/views/rooms/_EventBubbleTile.scss

@@ -38,8 +38,6 @@ limitations under the License.
         padding-top: 0;
     }
 
-    &:hover,
-    &.mx_EventTile_selected {
     &::before {
         content: '';
         position: absolute;
@@ -48,10 +46,16 @@ limitations under the License.
         left: -60px;
         right: -60px;
         z-index: -1;
-            background: $eventbubble-bg-hover;
         border-radius: 4px;
     }
 
+    &:hover,
+    &.mx_EventTile_selected {
+
+        &::before {
+            background: $eventbubble-bg-hover;
+        }
+
         .mx_EventTile_avatar {
             img {
                 box-shadow: 0 0 0 3px $eventbubble-bg-hover;
@@ -267,7 +271,7 @@ limitations under the License.
 
     display: flex;
     align-items: center;
-    justify-content: center;
+    justify-content: start;
     padding: 5px 0;
 
     .mx_EventTile_avatar {
@@ -275,12 +279,22 @@ limitations under the License.
         order: -1;
         margin-right: 5px;
     }
+
+    .mx_EventTile_e2eIcon {
+        margin-left: 9px;
+    }
+
+    .mx_EventTile_line > a {
+        right: auto;
+        top: -15px;
+        left: -68px;
+    }
 }
 
 .mx_EventListSummary[data-layout=bubble] {
-    --maxWidth: 80%;
+    --maxWidth: 70%;
     margin-left: calc(var(--avatarSize) + var(--gutterSize));
-    margin-right: calc(var(--gutterSize) + var(--avatarSize));
+    margin-right: 94px;
     .mx_EventListSummary_toggle {
         float: none;
         margin: 0;

res/css/views/rooms/_EventTile.scss

@@ -59,7 +59,6 @@ $hover-select-border: 4px;
         font-size: $font-14px;
         display: inline-block; /* anti-zalgo, with overflow hidden */
         overflow: hidden;
-        cursor: pointer;
         padding-bottom: 0px;
         padding-top: 0px;
         margin: 0px;
@@ -322,6 +321,10 @@ $hover-select-border: 4px;
     // on ELS we need the margin to allow interaction with the expand/collapse button which is normally in the RR gutter
 }
 
+.mx_SenderProfile {
+    cursor: pointer;
+}
+
 .mx_EventTile_bubbleContainer {
     display: grid;
     grid-template-columns: 1fr 100px;

src/components/structures/SpaceRoomDirectory.tsx

@@ -16,7 +16,6 @@ limitations under the License.
 
 import React, { ReactNode, useMemo, useState } from "react";
 import { Room } from "matrix-js-sdk/src/models/room";
-import { MatrixClient } from "matrix-js-sdk/src/client";
 import { EventType, RoomType } from "matrix-js-sdk/src/@types/event";
 import { ISpaceSummaryRoom, ISpaceSummaryEvent } from "matrix-js-sdk/src/@types/spaces";
 import classNames from "classnames";
@@ -44,11 +43,13 @@ import { getChildOrder } from "../../stores/SpaceStore";
 import AccessibleTooltipButton from "../views/elements/AccessibleTooltipButton";
 import { linkifyElement } from "../../HtmlUtils";
 import { getDisplayAliasForAliasSet } from "../../Rooms";
+import { useDispatcher } from "../../hooks/useDispatcher";
+import defaultDispatcher from "../../dispatcher/dispatcher";
+import { Action } from "../../dispatcher/actions";
 
 interface IHierarchyProps {
     space: Room;
     initialText?: string;
-    refreshToken?: any;
     additionalButtons?: ReactNode;
     showRoom(room: ISpaceSummaryRoom, viaServers?: string[], autoJoin?: boolean): void;
 }
@@ -315,18 +316,25 @@ export const HierarchyLevel = ({
     </React.Fragment>;
 };
 
-// mutate argument refreshToken to force a reload
+export const useSpaceSummary = (space: Room): [
-export const useSpaceSummary = (cli: MatrixClient, space: Room, refreshToken?: any): [
     null,
     ISpaceSummaryRoom[],
     Map<string, Map<string, ISpaceSummaryEvent>>?,
     Map<string, Set<string>>?,
     Map<string, Set<string>>?,
 ] | [Error] => {
+    // crude temporary refresh token approach until we have pagination and rework the data flow here
+    const [refreshToken, setRefreshToken] = useState(0);
+    useDispatcher(defaultDispatcher, (payload => {
+        if (payload.action === Action.UpdateSpaceHierarchy) {
+            setRefreshToken(t => t + 1);
+        }
+    }));
+
     // TODO pagination
     return useAsyncMemo(async () => {
         try {
-            const data = await cli.getSpaceSummary(space.roomId);
+            const data = await space.client.getSpaceSummary(space.roomId);
 
             const parentChildRelations = new EnhancedMap<string, Map<string, ISpaceSummaryEvent>>();
             const childParentRelations = new EnhancedMap<string, Set<string>>();
@@ -354,7 +362,6 @@ export const SpaceHierarchy: React.FC<IHierarchyProps> = ({
     space,
     initialText = "",
     showRoom,
-    refreshToken,
     additionalButtons,
     children,
 }) => {
@@ -364,7 +371,7 @@ export const SpaceHierarchy: React.FC<IHierarchyProps> = ({
 
     const [selected, setSelected] = useState(new Map<string, Set<string>>()); // Map<parentId, Set<childId>>
 
-    const [summaryError, rooms, parentChildMap, viaMap, childParentMap] = useSpaceSummary(cli, space, refreshToken);
+    const [summaryError, rooms, parentChildMap, viaMap, childParentMap] = useSpaceSummary(space);
 
     const roomsMap = useMemo(() => {
         if (!rooms) return null;

src/components/structures/SpaceRoomView.tsx

@@ -47,13 +47,23 @@ import { RightPanelPhases } from "../../stores/RightPanelStorePhases";
 import { SetRightPanelPhasePayload } from "../../dispatcher/payloads/SetRightPanelPhasePayload";
 import { useStateArray } from "../../hooks/useStateArray";
 import SpacePublicShare from "../views/spaces/SpacePublicShare";
-import { shouldShowSpaceSettings, showAddExistingRooms, showCreateNewRoom, showSpaceSettings } from "../../utils/space";
+import {
+    shouldShowSpaceSettings,
+    showAddExistingRooms,
+    showCreateNewRoom,
+    showCreateNewSubspace,
+    showSpaceSettings,
+} from "../../utils/space";
 import { showRoom, SpaceHierarchy } from "./SpaceRoomDirectory";
 import MemberAvatar from "../views/avatars/MemberAvatar";
-import { useStateToggle } from "../../hooks/useStateToggle";
 import SpaceStore from "../../stores/SpaceStore";
 import FacePile from "../views/elements/FacePile";
-import { AddExistingToSpace } from "../views/dialogs/AddExistingToSpaceDialog";
+import {
+    AddExistingToSpace,
+    defaultDmsRenderer,
+    defaultRoomsRenderer,
+    defaultSpacesRenderer,
+} from "../views/dialogs/AddExistingToSpaceDialog";
 import { ChevronFace, ContextMenuButton, useContextMenu } from "./ContextMenu";
 import IconizedContextMenu, {
     IconizedContextMenuOption,
@@ -283,7 +293,7 @@ const SpacePreview = ({ space, onJoinButtonClicked, onRejectButtonClicked }) =>
     </div>;
 };
 
-const SpaceLandingAddButton = ({ space, onNewRoomAdded }) => {
+const SpaceLandingAddButton = ({ space }) => {
     const [menuDisplayed, handle, openMenu, closeMenu] = useContextMenu();
 
     let contextMenu;
@@ -307,24 +317,32 @@ const SpaceLandingAddButton = ({ space, onNewRoomAdded }) => {
                         closeMenu();
 
                         if (await showCreateNewRoom(space)) {
-                            onNewRoomAdded();
+                            defaultDispatcher.fire(Action.UpdateSpaceHierarchy);
                         }
                     }}
                 />
                 <IconizedContextMenuOption
                     label={_t("Add existing room")}
                     iconClassName="mx_RoomList_iconHash"
-                    onClick={async (e) => {
+                    onClick={(e) => {
                         e.preventDefault();
                         e.stopPropagation();
                         closeMenu();
-
+                        showAddExistingRooms(space);
-                        const [added] = await showAddExistingRooms(space);
-                        if (added) {
-                            onNewRoomAdded();
-                        }
                     }}
                 />
+                <IconizedContextMenuOption
+                    label={_t("Add space")}
+                    iconClassName="mx_RoomList_iconPlus"
+                    onClick={(e) => {
+                        e.preventDefault();
+                        e.stopPropagation();
+                        closeMenu();
+                        showCreateNewSubspace(space);
+                    }}
+                >
+                    <BetaPill />
+                </IconizedContextMenuOption>
             </IconizedContextMenuOptionList>
         </IconizedContextMenu>;
     }
@@ -365,11 +383,9 @@ const SpaceLanding = ({ space }) => {
 
     const canAddRooms = myMembership === "join" && space.currentState.maySendStateEvent(EventType.SpaceChild, userId);
 
-    const [refreshToken, forceUpdate] = useStateToggle(false);
-
     let addRoomButton;
     if (canAddRooms) {
-        addRoomButton = <SpaceLandingAddButton space={space} onNewRoomAdded={forceUpdate} />;
+        addRoomButton = <SpaceLandingAddButton space={space} />;
     }
 
     let settingsButton;
@@ -418,12 +434,7 @@ const SpaceLanding = ({ space }) => {
             ) }
         </RoomTopic>
 
-        <SpaceHierarchy
+        <SpaceHierarchy space={space} showRoom={showRoom} additionalButtons={addRoomButton} />
-            space={space}
-            showRoom={showRoom}
-            refreshToken={refreshToken}
-            additionalButtons={addRoomButton}
-        />
     </div>;
 };
 
@@ -524,7 +535,11 @@ const SpaceAddExistingRooms = ({ space, onFinished }) => {
                     { _t("Skip for now") }
                 </AccessibleButton>
             }
+            filterPlaceholder={_t("Search for rooms or spaces")}
             onFinished={onFinished}
+            roomsRenderer={defaultRoomsRenderer}
+            spacesRenderer={defaultSpacesRenderer}
+            dmsRenderer={defaultDmsRenderer}
         />
     </div>;
 };

src/components/views/auth/CaptchaForm.tsx

@@ -103,8 +103,8 @@ export default class CaptchaForm extends React.Component<ICaptchaFormProps, ICap
     }
 
     private resetRecaptcha() {
-        if (this.captchaWidgetId !== null) {
+        if (this.captchaWidgetId) {
-            global.grecaptcha.reset(this.captchaWidgetId);
+            global?.grecaptcha?.reset(this.captchaWidgetId);
         }
     }
 

src/components/views/context_menus/IconizedContextMenu.tsx

@@ -90,10 +90,11 @@ export const IconizedContextMenuCheckbox: React.FC<ICheckboxProps> = ({
     </MenuItemCheckbox>;
 };
 
-export const IconizedContextMenuOption: React.FC<IOptionProps> = ({ label, iconClassName, ...props }) => {
+export const IconizedContextMenuOption: React.FC<IOptionProps> = ({ label, iconClassName, children, ...props }) => {
     return <MenuItem {...props} label={label}>
         { iconClassName && <span className={classNames("mx_IconizedContextMenu_icon", iconClassName)} /> }
         <span className="mx_IconizedContextMenu_label">{ label }</span>
+        { children }
     </MenuItem>;
 };
 

src/components/views/dialogs/AddExistingSubspaceDialog.tsx

@@ -0,0 +1,70 @@
+/*
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import React, { useState } from "react";
+import { Room } from "matrix-js-sdk/src/models/room";
+
+import { _t } from '../../../languageHandler';
+import BaseDialog from "./BaseDialog";
+import AccessibleButton from "../elements/AccessibleButton";
+import MatrixClientContext from "../../../contexts/MatrixClientContext";
+import { SpaceFeedbackPrompt } from "../../structures/SpaceRoomView";
+import { AddExistingToSpace, defaultSpacesRenderer, SubspaceSelector } from "./AddExistingToSpaceDialog";
+
+interface IProps {
+    space: Room;
+    onCreateSubspaceClick(): void;
+    onFinished(added?: boolean): void;
+}
+
+const AddExistingSubspaceDialog: React.FC<IProps> = ({ space, onCreateSubspaceClick, onFinished }) => {
+    const [selectedSpace, setSelectedSpace] = useState(space);
+
+    return <BaseDialog
+        title={(
+            <SubspaceSelector
+                title={_t("Add existing space")}
+                space={space}
+                value={selectedSpace}
+                onChange={setSelectedSpace}
+            />
+        )}
+        className="mx_AddExistingToSpaceDialog"
+        contentId="mx_AddExistingToSpace"
+        onFinished={onFinished}
+        fixedWidth={false}
+    >
+        <MatrixClientContext.Provider value={space.client}>
+            <AddExistingToSpace
+                space={space}
+                onFinished={onFinished}
+                footerPrompt={<>
+                    <div>{ _t("Want to add a new space instead?") }</div>
+                    <AccessibleButton onClick={onCreateSubspaceClick} kind="link">
+                        { _t("Create a new space") }
+                    </AccessibleButton>
+                </>}
+                filterPlaceholder={_t("Search for spaces")}
+                spacesRenderer={defaultSpacesRenderer}
+            />
+        </MatrixClientContext.Provider>
+
+        <SpaceFeedbackPrompt onClick={() => onFinished(false)} />
+    </BaseDialog>;
+};
+
+export default AddExistingSubspaceDialog;
+

src/components/views/dialogs/AddExistingToSpaceDialog.tsx

@@ -18,9 +18,9 @@ import React, { ReactNode, useContext, useMemo, useState } from "react";
 import classNames from "classnames";
 import { Room } from "matrix-js-sdk/src/models/room";
 import { sleep } from "matrix-js-sdk/src/utils";
+import { EventType } from "matrix-js-sdk/src/@types/event";
 
 import { _t } from '../../../languageHandler';
-import { IDialogProps } from "./IDialogProps";
 import BaseDialog from "./BaseDialog";
 import Dropdown from "../elements/Dropdown";
 import SearchBox from "../../structures/SearchBox";
@@ -41,12 +41,14 @@ import TruncatedList from "../elements/TruncatedList";
 import EntityTile from "../rooms/EntityTile";
 import BaseAvatar from "../avatars/BaseAvatar";
 
-interface IProps extends IDialogProps {
+interface IProps {
     space: Room;
-    onCreateRoomClick(space: Room): void;
+    onCreateRoomClick(): void;
+    onAddSubspaceClick(): void;
+    onFinished(added?: boolean): void;
 }
 
-const Entry = ({ room, checked, onChange }) => {
+export const Entry = ({ room, checked, onChange }) => {
     return <label className="mx_AddExistingToSpace_entry">
         { room?.isSpaceRoom()
             ? <RoomAvatar room={room} height={32} width={32} />
@@ -64,14 +66,36 @@ const Entry = ({ room, checked, onChange }) => {
 interface IAddExistingToSpaceProps {
     space: Room;
     footerPrompt?: ReactNode;
+    filterPlaceholder: string;
     emptySelectionButton?: ReactNode;
     onFinished(added: boolean): void;
+    roomsRenderer?(
+        rooms: Room[],
+        selectedToAdd: Set<Room>,
+        onChange: undefined | ((checked: boolean, room: Room) => void),
+        truncateAt: number,
+        overflowTile: (overflowCount: number, totalCount: number) => JSX.Element,
+    ): ReactNode;
+    spacesRenderer?(
+        spaces: Room[],
+        selectedToAdd: Set<Room>,
+        onChange?: (checked: boolean, room: Room) => void,
+    ): ReactNode;
+    dmsRenderer?(
+        dms: Room[],
+        selectedToAdd: Set<Room>,
+        onChange?: (checked: boolean, room: Room) => void,
+    ): ReactNode;
 }
 
 export const AddExistingToSpace: React.FC<IAddExistingToSpaceProps> = ({
     space,
     footerPrompt,
     emptySelectionButton,
+    filterPlaceholder,
+    roomsRenderer,
+    dmsRenderer,
+    spacesRenderer,
     onFinished,
 }) => {
     const cli = useContext(MatrixClientContext);
@@ -195,7 +219,7 @@ export const AddExistingToSpace: React.FC<IAddExistingToSpaceProps> = ({
         </>;
     }
 
-    const onChange = !busy && !error ? (checked, room) => {
+    const onChange = !busy && !error ? (checked: boolean, room: Room) => {
         if (checked) {
             selectedToAdd.add(room);
         } else {
@@ -205,7 +229,7 @@ export const AddExistingToSpace: React.FC<IAddExistingToSpaceProps> = ({
     } : null;
 
     const [truncateAt, setTruncateAt] = useState(20);
-    function overflowTile(overflowCount, totalCount) {
+    function overflowTile(overflowCount: number, totalCount: number): JSX.Element {
         const text = _t("and %(count)s others...", { count: overflowCount });
         return (
             <EntityTile
@@ -221,16 +245,49 @@ export const AddExistingToSpace: React.FC<IAddExistingToSpaceProps> = ({
         );
     }
 
+    let noResults = true;
+    if ((roomsRenderer && rooms.length > 0) ||
+        (dmsRenderer && dms.length > 0) ||
+        (!roomsRenderer && !dmsRenderer && spacesRenderer && spaces.length > 0) // only count spaces when alone
+    ) {
+        noResults = false;
+    }
+
     return <div className="mx_AddExistingToSpace">
         <SearchBox
             className="mx_textinput_icon mx_textinput_search"
-            placeholder={_t("Filter your rooms and spaces")}
+            placeholder={filterPlaceholder}
             onSearch={setQuery}
             autoComplete={true}
             autoFocus={true}
         />
         <AutoHideScrollbar className="mx_AddExistingToSpace_content">
-            { rooms.length > 0 ? (
+            { rooms.length > 0 && roomsRenderer ? (
+                roomsRenderer(rooms, selectedToAdd, onChange, truncateAt, overflowTile)
+            ) : undefined }
+
+            { spaces.length > 0 && spacesRenderer ? (
+                spacesRenderer(spaces, selectedToAdd, onChange)
+            ) : null }
+
+            { dms.length > 0 && dmsRenderer ? (
+                dmsRenderer(dms, selectedToAdd, onChange)
+            ) : null }
+
+            { noResults ? <span className="mx_AddExistingToSpace_noResults">
+                { _t("No results") }
+            </span> : undefined }
+        </AutoHideScrollbar>
+
+        <div className="mx_AddExistingToSpace_footer">
+            { footer }
+        </div>
+    </div>;
+};
+
+export const defaultRoomsRenderer: IAddExistingToSpaceProps["roomsRenderer"] = (
+    rooms, selectedToAdd, onChange, truncateAt, overflowTile,
+) => (
     <div className="mx_AddExistingToSpace_section">
         <h3>{ _t("Rooms") }</h3>
         <TruncatedList
@@ -241,7 +298,7 @@ export const AddExistingToSpace: React.FC<IAddExistingToSpaceProps> = ({
                     key={room.roomId}
                     room={room}
                     checked={selectedToAdd.has(room)}
-                                onChange={onChange ? (checked) => {
+                    onChange={onChange ? (checked: boolean) => {
                         onChange(checked, room);
                     } : null}
                 />,
@@ -249,15 +306,10 @@ export const AddExistingToSpace: React.FC<IAddExistingToSpaceProps> = ({
             getChildCount={() => rooms.length}
         />
     </div>
-            ) : undefined }
+);
 
-            { spaces.length > 0 ? (
+export const defaultSpacesRenderer: IAddExistingToSpaceProps["spacesRenderer"] = (spaces, selectedToAdd, onChange) => (
-                <div className="mx_AddExistingToSpace_section mx_AddExistingToSpace_section_spaces">
+    <div className="mx_AddExistingToSpace_section">
-                    <h3>{ _t("Spaces") }</h3>
-                    <div className="mx_AddExistingToSpace_section_experimental">
-                        <div>{ _t("Feeling experimental?") }</div>
-                        <div>{ _t("You can add existing spaces to a space.") }</div>
-                    </div>
         { spaces.map(space => {
             return <Entry
                 key={space.roomId}
@@ -269,9 +321,9 @@ export const AddExistingToSpace: React.FC<IAddExistingToSpaceProps> = ({
             />;
         }) }
     </div>
-            ) : null }
+);
 
-            { dms.length > 0 ? (
+export const defaultDmsRenderer: IAddExistingToSpaceProps["dmsRenderer"] = (dms, selectedToAdd, onChange) => (
     <div className="mx_AddExistingToSpace_section">
         <h3>{ _t("Direct Messages") }</h3>
         { dms.map(room => {
@@ -279,69 +331,80 @@ export const AddExistingToSpace: React.FC<IAddExistingToSpaceProps> = ({
                 key={room.roomId}
                 room={room}
                 checked={selectedToAdd.has(room)}
-                            onChange={onChange ? (checked) => {
+                onChange={onChange ? (checked: boolean) => {
                     onChange(checked, room);
                 } : null}
             />;
         }) }
     </div>
-            ) : null }
+);
 
-            { spaces.length + rooms.length + dms.length < 1 ? <span className="mx_AddExistingToSpace_noResults">
+interface ISubspaceSelectorProps {
-                { _t("No results") }
+    title: string;
-            </span> : undefined }
+    space: Room;
-        </AutoHideScrollbar>
+    value: Room;
+    onChange(space: Room): void;
+}
 
-        <div className="mx_AddExistingToSpace_footer">
+export const SubspaceSelector = ({ title, space, value, onChange }: ISubspaceSelectorProps) => {
-            { footer }
+    const options = useMemo(() => {
-        </div>
+        return [space, ...SpaceStore.instance.getChildSpaces(space.roomId).filter(space => {
-    </div>;
+            return space.currentState.maySendStateEvent(EventType.SpaceChild, space.client.credentials.userId);
-};
+        })];
+    }, [space]);
 
-const AddExistingToSpaceDialog: React.FC<IProps> = ({ space, onCreateRoomClick, onFinished }) => {
+    let body;
-    const [selectedSpace, setSelectedSpace] = useState(space);
+    if (options.length > 1) {
-    const existingSubspaces = SpaceStore.instance.getChildSpaces(space.roomId);
+        body = (
-
+            <Dropdown
-    let spaceOptionSection;
+                id="mx_SpaceSelectDropdown"
-    if (existingSubspaces.length > 0) {
+                className="mx_SpaceSelectDropdown"
-        const options = [space, ...existingSubspaces].map((space) => {
+                onOptionChange={(key: string) => {
-            const classes = classNames("mx_AddExistingToSpaceDialog_dropdownOption", {
+                    onChange(options.find(space => space.roomId === key) || space);
-                mx_AddExistingToSpaceDialog_dropdownOptionActive: space === selectedSpace,
+                }}
+                value={value.roomId}
+                label={_t("Space selection")}
+            >
+                { options.map((space) => {
+                    const classes = classNames({
+                        mx_SubspaceSelector_dropdownOptionActive: space === value,
                     });
                     return <div key={space.roomId} className={classes}>
                         <RoomAvatar room={space} width={24} height={24} />
                         { space.name || getDisplayAliasForRoom(space) || space.roomId }
                     </div>;
-        });
+                }) }
-
-        spaceOptionSection = (
-            <Dropdown
-                id="mx_SpaceSelectDropdown"
-                onOptionChange={(key: string) => {
-                    setSelectedSpace(existingSubspaces.find(space => space.roomId === key) || space);
-                }}
-                value={selectedSpace.roomId}
-                label={_t("Space selection")}
-            >
-                { options }
             </Dropdown>
         );
     } else {
-        spaceOptionSection = <div className="mx_AddExistingToSpaceDialog_onlySpace">
+        body = (
+            <div className="mx_SubspaceSelector_onlySpace">
                 { space.name || getDisplayAliasForRoom(space) || space.roomId }
-        </div>;
+            </div>
+        );
     }
 
-    const title = <React.Fragment>
+    return <div className="mx_SubspaceSelector">
-        <RoomAvatar room={selectedSpace} height={40} width={40} />
+        <RoomAvatar room={value} height={40} width={40} />
         <div>
-            <h1>{ _t("Add existing rooms") }</h1>
+            <h1>{ title }</h1>
-            { spaceOptionSection }
+            { body }
         </div>
-    </React.Fragment>;
+    </div>;
+};
+
+const AddExistingToSpaceDialog: React.FC<IProps> = ({ space, onCreateRoomClick, onAddSubspaceClick, onFinished }) => {
+    const [selectedSpace, setSelectedSpace] = useState(space);
 
     return <BaseDialog
-        title={title}
+        title={(
+            <SubspaceSelector
+                title={_t("Add existing rooms")}
+                space={space}
+                value={selectedSpace}
+                onChange={setSelectedSpace}
+            />
+        )}
         className="mx_AddExistingToSpaceDialog"
         contentId="mx_AddExistingToSpace"
         onFinished={onFinished}
@@ -353,10 +416,33 @@ const AddExistingToSpaceDialog: React.FC<IProps> = ({ space, onCreateRoomClick,
                 onFinished={onFinished}
                 footerPrompt={<>
                     <div>{ _t("Want to add a new room instead?") }</div>
-                    <AccessibleButton onClick={() => onCreateRoomClick(space)} kind="link">
+                    <AccessibleButton
+                        kind="link"
+                        onClick={() => {
+                            onCreateRoomClick();
+                            onFinished();
+                        }}
+                    >
                         { _t("Create a new room") }
                     </AccessibleButton>
                 </>}
+                filterPlaceholder={_t("Search for rooms")}
+                roomsRenderer={defaultRoomsRenderer}
+                spacesRenderer={() => (
+                    <div className="mx_AddExistingToSpace_section">
+                        <h3>{ _t("Spaces") }</h3>
+                        <AccessibleButton
+                            kind="link"
+                            onClick={() => {
+                                onAddSubspaceClick();
+                                onFinished();
+                            }}
+                        >
+                            { _t("Adding spaces has moved.") }
+                        </AccessibleButton>
+                    </div>
+                )}
+                dmsRenderer={defaultDmsRenderer}
             />
         </MatrixClientContext.Provider>
     </BaseDialog>;

src/components/views/dialogs/CreateRoomDialog.tsx

@@ -32,8 +32,8 @@ import RoomAliasField from "../elements/RoomAliasField";
 import LabelledToggleSwitch from "../elements/LabelledToggleSwitch";
 import DialogButtons from "../elements/DialogButtons";
 import BaseDialog from "../dialogs/BaseDialog";
-import Dropdown from "../elements/Dropdown";
 import SpaceStore from "../../../stores/SpaceStore";
+import JoinRuleDropdown from "../elements/JoinRuleDropdown";
 
 interface IProps {
     defaultPublic?: boolean;
@@ -322,21 +322,6 @@ export default class CreateRoomDialog extends React.Component<IProps, IState> {
             title = this.state.joinRule === JoinRule.Public ? _t('Create a public room') : _t('Create a private room');
         }
 
-        const options = [
-            <div key={JoinRule.Invite} className="mx_CreateRoomDialog_dropdown_invite">
-                { _t("Private room (invite only)") }
-            </div>,
-            <div key={JoinRule.Public} className="mx_CreateRoomDialog_dropdown_public">
-                { _t("Public room") }
-            </div>,
-        ];
-
-        if (this.supportsRestricted) {
-            options.unshift(<div key={JoinRule.Restricted} className="mx_CreateRoomDialog_dropdown_restricted">
-                { _t("Visible to space members") }
-            </div>);
-        }
-
         return (
             <BaseDialog className="mx_CreateRoomDialog" onFinished={this.props.onFinished} title={title}>
                 <form onSubmit={this.onOk} onKeyDown={this.onKeyDown}>
@@ -356,16 +341,14 @@ export default class CreateRoomDialog extends React.Component<IProps, IState> {
                             className="mx_CreateRoomDialog_topic"
                         />
 
-                        <Dropdown
+                        <JoinRuleDropdown
-                            id="mx_CreateRoomDialog_typeDropdown"
-                            className="mx_CreateRoomDialog_typeDropdown"
-                            onOptionChange={this.onJoinRuleChange}
-                            menuWidth={448}
-                            value={this.state.joinRule}
                             label={_t("Room visibility")}
-                        >
+                            labelInvite={_t("Private room (invite only)")}
-                            { options }
+                            labelPublic={_t("Public room")}
-                        </Dropdown>
+                            labelRestricted={this.supportsRestricted ? _t("Visible to space members") : undefined}
+                            value={this.state.joinRule}
+                            onChange={this.onJoinRuleChange}
+                        />
 
                         { publicPrivateLabel }
                         { e2eeSection }

src/components/views/dialogs/CreateSubspaceDialog.tsx

@@ -0,0 +1,210 @@
+/*
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import React, { useRef, useState } from "react";
+import { Room } from "matrix-js-sdk/src/models/room";
+import { JoinRule, Preset } from "matrix-js-sdk/src/@types/partials";
+import { RoomType } from "matrix-js-sdk/src/@types/event";
+
+import { _t } from '../../../languageHandler';
+import BaseDialog from "./BaseDialog";
+import AccessibleButton from "../elements/AccessibleButton";
+import MatrixClientContext from "../../../contexts/MatrixClientContext";
+import { BetaPill } from "../beta/BetaCard";
+import Field from "../elements/Field";
+import RoomAliasField from "../elements/RoomAliasField";
+import SpaceStore from "../../../stores/SpaceStore";
+import { SpaceCreateForm } from "../spaces/SpaceCreateMenu";
+import createRoom from "../../../createRoom";
+import { SubspaceSelector } from "./AddExistingToSpaceDialog";
+import JoinRuleDropdown from "../elements/JoinRuleDropdown";
+
+interface IProps {
+    space: Room;
+    onAddExistingSpaceClick(): void;
+    onFinished(added?: boolean): void;
+}
+
+const CreateSubspaceDialog: React.FC<IProps> = ({ space, onAddExistingSpaceClick, onFinished }) => {
+    const [parentSpace, setParentSpace] = useState(space);
+
+    const [busy, setBusy] = useState<boolean>(false);
+    const [name, setName] = useState("");
+    const spaceNameField = useRef<Field>();
+    const [alias, setAlias] = useState("");
+    const spaceAliasField = useRef<RoomAliasField>();
+    const [avatar, setAvatar] = useState<File>(null);
+    const [topic, setTopic] = useState<string>("");
+
+    const supportsRestricted = !!SpaceStore.instance.restrictedJoinRuleSupport?.preferred;
+
+    const spaceJoinRule = space.getJoinRule();
+    let defaultJoinRule = JoinRule.Invite;
+    if (spaceJoinRule === JoinRule.Public) {
+        defaultJoinRule = JoinRule.Public;
+    } else if (supportsRestricted) {
+        defaultJoinRule = JoinRule.Restricted;
+    }
+    const [joinRule, setJoinRule] = useState<JoinRule>(defaultJoinRule);
+
+    const onCreateSubspaceClick = async (e) => {
+        e.preventDefault();
+        if (busy) return;
+
+        setBusy(true);
+        // require & validate the space name field
+        if (!await spaceNameField.current.validate({ allowEmpty: false })) {
+            spaceNameField.current.focus();
+            spaceNameField.current.validate({ allowEmpty: false, focused: true });
+            setBusy(false);
+            return;
+        }
+        // validate the space name alias field but do not require it
+        if (joinRule === JoinRule.Public && !await spaceAliasField.current.validate({ allowEmpty: true })) {
+            spaceAliasField.current.focus();
+            spaceAliasField.current.validate({ allowEmpty: true, focused: true });
+            setBusy(false);
+            return;
+        }
+
+        try {
+            await createRoom({
+                createOpts: {
+                    preset: joinRule === JoinRule.Public ? Preset.PublicChat : Preset.PrivateChat,
+                    name,
+                    power_level_content_override: {
+                        // Only allow Admins to write to the timeline to prevent hidden sync spam
+                        events_default: 100,
+                        ...joinRule === JoinRule.Public ? { invite: 0 } : {},
+                    },
+                    room_alias_name: joinRule === JoinRule.Public && alias
+                        ? alias.substr(1, alias.indexOf(":") - 1)
+                        : undefined,
+                    topic,
+                },
+                avatar,
+                roomType: RoomType.Space,
+                parentSpace,
+                spinner: false,
+                encryption: false,
+                andView: true,
+                inlineErrors: true,
+            });
+
+            onFinished(true);
+        } catch (e) {
+            console.error(e);
+        }
+    };
+
+    let joinRuleMicrocopy: JSX.Element;
+    if (joinRule === JoinRule.Restricted) {
+        joinRuleMicrocopy = <p>
+            { _t(
+                "Anyone in <SpaceName/> will be able to find and join.", {}, {
+                    SpaceName: () => <b>{ parentSpace.name }</b>,
+                },
+            ) }
+        </p>;
+    } else if (joinRule === JoinRule.Public) {
+        joinRuleMicrocopy = <p>
+            { _t(
+                "Anyone will be able to find and join this space, not just members of <SpaceName/>.", {}, {
+                    SpaceName: () => <b>{ parentSpace.name }</b>,
+                },
+            ) }
+        </p>;
+    } else if (joinRule === JoinRule.Invite) {
+        joinRuleMicrocopy = <p>
+            { _t("Only people invited will be able to find and join this space.") }
+        </p>;
+    }
+
+    return <BaseDialog
+        title={(
+            <SubspaceSelector
+                title={_t("Create a space")}
+                space={space}
+                value={parentSpace}
+                onChange={setParentSpace}
+            />
+        )}
+        className="mx_CreateSubspaceDialog"
+        contentId="mx_CreateSubspaceDialog"
+        onFinished={onFinished}
+        fixedWidth={false}
+    >
+        <MatrixClientContext.Provider value={space.client}>
+            <div className="mx_CreateSubspaceDialog_content">
+                <div className="mx_CreateSubspaceDialog_betaNotice">
+                    <BetaPill />
+                    { _t("Add a space to a space you manage.") }
+                </div>
+
+                <SpaceCreateForm
+                    busy={busy}
+                    onSubmit={onCreateSubspaceClick}
+                    setAvatar={setAvatar}
+                    name={name}
+                    setName={setName}
+                    nameFieldRef={spaceNameField}
+                    topic={topic}
+                    setTopic={setTopic}
+                    alias={alias}
+                    setAlias={setAlias}
+                    showAliasField={joinRule === JoinRule.Public}
+                    aliasFieldRef={spaceAliasField}
+                >
+                    <JoinRuleDropdown
+                        label={_t("Space visibility")}
+                        labelInvite={_t("Private space (invite only)")}
+                        labelPublic={_t("Public space")}
+                        labelRestricted={supportsRestricted ? _t("Visible to space members") : undefined}
+                        width={478}
+                        value={joinRule}
+                        onChange={setJoinRule}
+                    />
+                    { joinRuleMicrocopy }
+                </SpaceCreateForm>
+            </div>
+
+            <div className="mx_CreateSubspaceDialog_footer">
+                <div className="mx_CreateSubspaceDialog_footer_prompt">
+                    <div>{ _t("Want to add an existing space instead?") }</div>
+                    <AccessibleButton
+                        kind="link"
+                        onClick={() => {
+                            onAddExistingSpaceClick();
+                            onFinished();
+                        }}
+                    >
+                        { _t("Add existing space") }
+                    </AccessibleButton>
+                </div>
+
+                <AccessibleButton kind="primary_outline" disabled={busy} onClick={() => onFinished(false)}>
+                    { _t("Cancel") }
+                </AccessibleButton>
+                <AccessibleButton kind="primary" disabled={busy} onClick={onCreateSubspaceClick}>
+                    { busy ? _t("Adding...") : _t("Add") }
+                </AccessibleButton>
+            </div>
+        </MatrixClientContext.Provider>
+    </BaseDialog>;
+};
+
+export default CreateSubspaceDialog;
+

src/components/views/elements/JoinRuleDropdown.tsx

@@ -0,0 +1,68 @@
+/*
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import React from 'react';
+import { JoinRule } from 'matrix-js-sdk/src/@types/partials';
+
+import Dropdown from "./Dropdown";
+
+interface IProps {
+    value: JoinRule;
+    label: string;
+    width?: number;
+    labelInvite: string;
+    labelPublic: string;
+    labelRestricted?: string; // if omitted then this option will be hidden, e.g if unsupported
+    onChange(value: JoinRule): void;
+}
+
+const JoinRuleDropdown = ({
+    label,
+    labelInvite,
+    labelPublic,
+    labelRestricted,
+    value,
+    width = 448,
+    onChange,
+}: IProps) => {
+    const options = [
+        <div key={JoinRule.Invite} className="mx_JoinRuleDropdown_invite">
+            { labelInvite }
+        </div>,
+        <div key={JoinRule.Public} className="mx_JoinRuleDropdown_public">
+            { labelPublic }
+        </div>,
+    ];
+
+    if (labelRestricted) {
+        options.unshift(<div key={JoinRule.Restricted} className="mx_JoinRuleDropdown_restricted">
+            { labelRestricted }
+        </div>);
+    }
+
+    return <Dropdown
+        id="mx_JoinRuleDropdown"
+        className="mx_JoinRuleDropdown"
+        onOptionChange={onChange}
+        menuWidth={width}
+        value={value}
+        label={label}
+    >
+        { options }
+    </Dropdown>;
+};
+
+export default JoinRuleDropdown;

src/components/views/messages/ViewSourceEvent.tsx

@@ -15,18 +15,21 @@ limitations under the License.
 */
 
 import React from 'react';
-import PropTypes from 'prop-types';
+import { MatrixEvent } from 'matrix-js-sdk/src';
 import classNames from 'classnames';
 import { replaceableComponent } from "../../../utils/replaceableComponent";
 import { MatrixClientPeg } from "../../../MatrixClientPeg";
 
-@replaceableComponent("views.messages.ViewSourceEvent")
+interface IProps {
-export default class ViewSourceEvent extends React.PureComponent {
+    mxEvent: MatrixEvent;
-    static propTypes = {
+}
-        /* the MatrixEvent to show */
-        mxEvent: PropTypes.object.isRequired,
-    };
 
+interface IState {
+    expanded: boolean;
+}
+
+@replaceableComponent("views.messages.ViewSourceEvent")
+export default class ViewSourceEvent extends React.PureComponent<IProps, IState> {
     constructor(props) {
         super(props);
 
@@ -35,7 +38,7 @@ export default class ViewSourceEvent extends React.PureComponent {
         };
     }
 
-    componentDidMount() {
+    public componentDidMount(): void {
         const { mxEvent } = this.props;
 
         const client = MatrixClientPeg.get();
@@ -46,15 +49,15 @@ export default class ViewSourceEvent extends React.PureComponent {
         }
     }
 
-    onToggle = (ev) => {
+    private onToggle = (ev: React.MouseEvent) => {
         ev.preventDefault();
         const { expanded } = this.state;
         this.setState({
             expanded: !expanded,
         });
-    }
+    };
 
-    render() {
+    public render(): React.ReactNode {
         const { mxEvent } = this.props;
         const { expanded } = this.state;
 

src/components/views/spaces/SpaceCreateMenu.tsx

@@ -14,9 +14,9 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import React, { useContext, useRef, useState } from "react";
+import React, { ComponentProps, RefObject, SyntheticEvent, useContext, useRef, useState } from "react";
 import classNames from "classnames";
-import { EventType, RoomType, RoomCreateTypeField } from "matrix-js-sdk/src/@types/event";
+import { RoomType } from "matrix-js-sdk/src/@types/event";
 import FocusLock from "react-focus-lock";
 
 import { _t } from "../../../languageHandler";
@@ -24,12 +24,11 @@ import AccessibleTooltipButton from "../elements/AccessibleTooltipButton";
 import { ChevronFace, ContextMenu } from "../../structures/ContextMenu";
 import createRoom from "../../../createRoom";
 import MatrixClientContext from "../../../contexts/MatrixClientContext";
-import { SpaceAvatar } from "./SpaceBasicSettings";
+import SpaceBasicSettings, { SpaceAvatar } from "./SpaceBasicSettings";
 import AccessibleButton from "../elements/AccessibleButton";
 import Field from "../elements/Field";
 import withValidation from "../elements/Validation";
-import { Preset } from "matrix-js-sdk/src/@types/partials";
+import { HistoryVisibility, Preset } from "matrix-js-sdk/src/@types/partials";
-import { ICreateRoomStateEvent } from "matrix-js-sdk/src/@types/requests";
 import RoomAliasField from "../elements/RoomAliasField";
 import SdkConfig from "../../../SdkConfig";
 import Modal from "../../../Modal";
@@ -93,8 +92,83 @@ export const SpaceFeedbackPrompt = ({ onClick }: { onClick?: () => void }) => {
     </div>;
 };
 
-const SpaceCreateMenu = ({ onFinished }) => {
+type BProps = Pick<ComponentProps<typeof SpaceBasicSettings>, "setAvatar" | "name" | "setName" | "topic" | "setTopic">;
+interface ISpaceCreateFormProps extends BProps {
+    busy: boolean;
+    alias: string;
+    nameFieldRef: RefObject<Field>;
+    aliasFieldRef: RefObject<RoomAliasField>;
+    showAliasField?: boolean;
+    onSubmit(e: SyntheticEvent): void;
+    setAlias(alias: string): void;
+}
+
+export const SpaceCreateForm: React.FC<ISpaceCreateFormProps> = ({
+    busy,
+    onSubmit,
+    setAvatar,
+    name,
+    setName,
+    nameFieldRef,
+    alias,
+    aliasFieldRef,
+    setAlias,
+    showAliasField,
+    topic,
+    setTopic,
+    children,
+}) => {
     const cli = useContext(MatrixClientContext);
+    const domain = cli.getDomain();
+
+    return <form className="mx_SpaceBasicSettings" onSubmit={onSubmit}>
+        <SpaceAvatar setAvatar={setAvatar} avatarDisabled={busy} />
+
+        <Field
+            name="spaceName"
+            label={_t("Name")}
+            autoFocus={true}
+            value={name}
+            onChange={ev => {
+                const newName = ev.target.value;
+                if (!alias || alias === nameToAlias(name, domain)) {
+                    setAlias(nameToAlias(newName, domain));
+                }
+                setName(newName);
+            }}
+            ref={nameFieldRef}
+            onValidate={spaceNameValidator}
+            disabled={busy}
+        />
+
+        { showAliasField
+            ? <RoomAliasField
+                ref={aliasFieldRef}
+                onChange={setAlias}
+                domain={domain}
+                value={alias}
+                placeholder={name ? nameToAlias(name, domain) : _t("e.g. my-space")}
+                label={_t("Address")}
+                disabled={busy}
+            />
+            : null
+        }
+
+        <Field
+            name="spaceTopic"
+            element="textarea"
+            label={_t("Description")}
+            value={topic}
+            onChange={ev => setTopic(ev.target.value)}
+            rows={3}
+            disabled={busy}
+        />
+
+        { children }
+    </form>;
+};
+
+const SpaceCreateMenu = ({ onFinished }) => {
     const [visibility, setVisibility] = useState<Visibility>(null);
     const [busy, setBusy] = useState<boolean>(false);
 
@@ -125,42 +199,26 @@ const SpaceCreateMenu = ({ onFinished }) => {
             return;
         }
 
-        const initialState: ICreateRoomStateEvent[] = [
-            {
-                type: EventType.RoomHistoryVisibility,
-                content: {
-                    "history_visibility": visibility === Visibility.Public ? "world_readable" : "invited",
-                },
-            },
-        ];
-        if (avatar) {
-            const url = await cli.uploadContent(avatar);
-
-            initialState.push({
-                type: EventType.RoomAvatar,
-                content: { url },
-            });
-        }
-
         try {
             await createRoom({
                 createOpts: {
                     preset: visibility === Visibility.Public ? Preset.PublicChat : Preset.PrivateChat,
                     name,
-                    creation_content: {
-                        [RoomCreateTypeField]: RoomType.Space,
-                    },
-                    initial_state: initialState,
                     power_level_content_override: {
                         // Only allow Admins to write to the timeline to prevent hidden sync spam
                         events_default: 100,
-                        ...Visibility.Public ? { invite: 0 } : {},
+                        ...visibility === Visibility.Public ? { invite: 0 } : {},
                     },
                     room_alias_name: visibility === Visibility.Public && alias
                         ? alias.substr(1, alias.indexOf(":") - 1)
                         : undefined,
                     topic,
                 },
+                avatar,
+                roomType: RoomType.Space,
+                historyVisibility: visibility === Visibility.Public
+                    ? HistoryVisibility.WorldReadable
+                    : HistoryVisibility.Invited,
                 spinner: false,
                 encryption: false,
                 andView: true,
@@ -198,7 +256,6 @@ const SpaceCreateMenu = ({ onFinished }) => {
             <SpaceFeedbackPrompt onClick={onFinished} />
         </React.Fragment>;
     } else {
-        const domain = cli.getDomain();
         body = <React.Fragment>
             <AccessibleTooltipButton
                 className="mx_SpaceCreateMenu_back"
@@ -219,50 +276,21 @@ const SpaceCreateMenu = ({ onFinished }) => {
                 }
             </p>
 
-            <form className="mx_SpaceBasicSettings" onSubmit={onSpaceCreateClick}>
+            <SpaceCreateForm
-                <SpaceAvatar setAvatar={setAvatar} avatarDisabled={busy} />
+                busy={busy}
-
+                onSubmit={onSpaceCreateClick}
-                <Field
+                setAvatar={setAvatar}
-                    name="spaceName"
+                name={name}
-                    label={_t("Name")}
+                setName={setName}
-                    autoFocus={true}
+                nameFieldRef={spaceNameField}
-                    value={name}
+                topic={topic}
-                    onChange={ev => {
+                setTopic={setTopic}
-                        const newName = ev.target.value;
+                alias={alias}
-                        if (!alias || alias === nameToAlias(name, domain)) {
+                setAlias={setAlias}
-                            setAlias(nameToAlias(newName, domain));
+                showAliasField={visibility === Visibility.Public}
-                        }
+                aliasFieldRef={spaceAliasField}
-                        setName(newName);
-                    }}
-                    ref={spaceNameField}
-                    onValidate={spaceNameValidator}
-                    disabled={busy}
             />
 
-                { visibility === Visibility.Public
-                    ? <RoomAliasField
-                        ref={spaceAliasField}
-                        onChange={setAlias}
-                        domain={domain}
-                        value={alias}
-                        placeholder={name ? nameToAlias(name, domain) : _t("e.g. my-space")}
-                        label={_t("Address")}
-                        disabled={busy}
-                    />
-                    : null
-                }
-
-                <Field
-                    name="spaceTopic"
-                    element="textarea"
-                    label={_t("Description")}
-                    value={topic}
-                    onChange={ev => setTopic(ev.target.value)}
-                    rows={3}
-                    disabled={busy}
-                />
-            </form>
-
             <AccessibleButton kind="primary" onClick={onSpaceCreateClick} disabled={busy}>
                 { busy ? _t("Creating...") : _t("Create") }
             </AccessibleButton>

src/components/views/spaces/SpaceTreeLevel.tsx

@@ -34,6 +34,7 @@ import {
     shouldShowSpaceSettings,
     showAddExistingRooms,
     showCreateNewRoom,
+    showCreateNewSubspace,
     showSpaceInvite,
     showSpaceSettings,
 } from "../../../utils/space";
@@ -48,6 +49,7 @@ import { EventType } from "matrix-js-sdk/src/@types/event";
 import { StaticNotificationState } from "../../../stores/notifications/StaticNotificationState";
 import { NotificationColor } from "../../../stores/notifications/NotificationColor";
 import { getKeyBindingsManager, RoomListAction } from "../../../KeyBindingsManager";
+import { BetaPill } from "../beta/BetaCard";
 
 interface IItemProps extends InputHTMLAttributes<HTMLLIElement> {
     space?: Room;
@@ -234,6 +236,14 @@ export class SpaceItem extends React.PureComponent<IItemProps, IItemState> {
         this.setState({ contextMenuPosition: null }); // also close the menu
     };
 
+    private onNewSubspaceClick = (ev: ButtonEvent) => {
+        ev.preventDefault();
+        ev.stopPropagation();
+
+        showCreateNewSubspace(this.props.space);
+        this.setState({ contextMenuPosition: null }); // also close the menu
+    };
+
     private onMembersClick = (ev: ButtonEvent) => {
         ev.preventDefault();
         ev.stopPropagation();
@@ -318,6 +328,13 @@ export class SpaceItem extends React.PureComponent<IItemProps, IItemState> {
                         label={_t("Add existing room")}
                         onClick={this.onAddExistingRoomClick}
                     />
+                    <IconizedContextMenuOption
+                        iconClassName="mx_SpacePanel_iconPlus"
+                        label={_t("Add space")}
+                        onClick={this.onNewSubspaceClick}
+                    >
+                        <BetaPill />
+                    </IconizedContextMenuOption>
                 </IconizedContextMenuOptionList>;
             }
 

src/createRoom.ts

@@ -18,9 +18,15 @@ limitations under the License.
 import { MatrixClient } from "matrix-js-sdk/src/client";
 import { Room } from "matrix-js-sdk/src/models/room";
 import { RoomMember } from "matrix-js-sdk/src/models/room-member";
-import { EventType } from "matrix-js-sdk/src/@types/event";
+import { EventType, RoomCreateTypeField, RoomType } from "matrix-js-sdk/src/@types/event";
 import { ICreateRoomOpts } from "matrix-js-sdk/src/@types/requests";
-import { JoinRule, Preset, RestrictedAllowType, Visibility } from "matrix-js-sdk/src/@types/partials";
+import {
+    HistoryVisibility,
+    JoinRule,
+    Preset,
+    RestrictedAllowType,
+    Visibility,
+} from "matrix-js-sdk/src/@types/partials";
 
 import { MatrixClientPeg } from './MatrixClientPeg';
 import Modal from './Modal';
@@ -52,6 +58,9 @@ export interface IOpts {
     inlineErrors?: boolean;
     andView?: boolean;
     associatedWithCommunity?: string;
+    avatar?: File | string; // will upload if given file, else mxcUrl is needed
+    roomType?: RoomType | string;
+    historyVisibility?: HistoryVisibility;
     parentSpace?: Room;
     joinRule?: JoinRule;
 }
@@ -112,6 +121,13 @@ export default async function createRoom(opts: IOpts): Promise<string | null> {
         createOpts.is_direct = true;
     }
 
+    if (opts.roomType) {
+        createOpts.creation_content = {
+            ...createOpts.creation_content,
+            [RoomCreateTypeField]: opts.roomType,
+        };
+    }
+
     // By default, view the room after creating it
     if (opts.andView === undefined) {
         opts.andView = true;
@@ -144,12 +160,11 @@ export default async function createRoom(opts: IOpts): Promise<string | null> {
 
     if (opts.parentSpace) {
         createOpts.initial_state.push(makeSpaceParentEvent(opts.parentSpace, true));
-        createOpts.initial_state.push({
+        if (!opts.historyVisibility) {
-            type: EventType.RoomHistoryVisibility,
+            opts.historyVisibility = createOpts.preset === Preset.PublicChat
-            content: {
+                ? HistoryVisibility.WorldReadable
-                "history_visibility": createOpts.preset === Preset.PublicChat ? "world_readable" : "invited",
+                : HistoryVisibility.Invited;
-            },
+        }
-        });
 
         if (opts.joinRule === JoinRule.Restricted) {
             if (SpaceStore.instance.restrictedJoinRuleSupport?.preferred) {
@@ -176,6 +191,27 @@ export default async function createRoom(opts: IOpts): Promise<string | null> {
         });
     }
 
+    if (opts.avatar) {
+        let url = opts.avatar;
+        if (opts.avatar instanceof File) {
+            url = await client.uploadContent(opts.avatar);
+        }
+
+        createOpts.initial_state.push({
+            type: EventType.RoomAvatar,
+            content: { url },
+        });
+    }
+
+    if (opts.historyVisibility) {
+        createOpts.initial_state.push({
+            type: EventType.RoomHistoryVisibility,
+            content: {
+                "history_visibility": opts.historyVisibility,
+            },
+        });
+    }
+
     let modal;
     if (opts.spinner) modal = Modal.createDialog(Spinner, null, 'mx_Dialog_spinner');
 

src/dispatcher/actions.ts

@@ -193,4 +193,9 @@ export enum Action {
      * Switches space. Should be used with SwitchSpacePayload.
      */
     SwitchSpace = "switch_space",
+
+    /**
+     * Signals to the visible space hierarchy that a change has occurred an that it should refresh.
+     */
+    UpdateSpaceHierarchy = "update_space_hierarchy",
 }

src/i18n/strings/en_EN.json

@@ -1009,6 +1009,8 @@
     "Spaces feedback": "Spaces feedback",
     "Thank you for trying Spaces. Your feedback will help inform the next versions.": "Thank you for trying Spaces. Your feedback will help inform the next versions.",
     "Give feedback.": "Give feedback.",
+    "e.g. my-space": "e.g. my-space",
+    "Address": "Address",
     "Create a space": "Create a space",
     "Spaces are a new way to group rooms and people. To join an existing space you'll need an invite.": "Spaces are a new way to group rooms and people. To join an existing space you'll need an invite.",
     "Public": "Public",
@@ -1021,8 +1023,6 @@
     "Your private space": "Your private space",
     "Add some details to help people recognise it.": "Add some details to help people recognise it.",
     "You can change these anytime.": "You can change these anytime.",
-    "e.g. my-space": "e.g. my-space",
-    "Address": "Address",
     "Creating...": "Creating...",
     "Create": "Create",
     "All rooms": "All rooms",
@@ -1060,6 +1060,7 @@
     "Leave space": "Leave space",
     "Create new room": "Create new room",
     "Add existing room": "Add existing room",
+    "Add space": "Add space",
     "Members": "Members",
     "Manage & explore rooms": "Manage & explore rooms",
     "Explore rooms": "Explore rooms",
@@ -2114,17 +2115,20 @@
     "Add a new server...": "Add a new server...",
     "%(networkName)s rooms": "%(networkName)s rooms",
     "Matrix rooms": "Matrix rooms",
+    "Add existing space": "Add existing space",
+    "Want to add a new space instead?": "Want to add a new space instead?",
+    "Create a new space": "Create a new space",
+    "Search for spaces": "Search for spaces",
     "Not all selected were added": "Not all selected were added",
     "Adding rooms... (%(progress)s out of %(count)s)|other": "Adding rooms... (%(progress)s out of %(count)s)",
     "Adding rooms... (%(progress)s out of %(count)s)|one": "Adding room...",
-    "Filter your rooms and spaces": "Filter your rooms and spaces",
-    "Feeling experimental?": "Feeling experimental?",
-    "You can add existing spaces to a space.": "You can add existing spaces to a space.",
     "Direct Messages": "Direct Messages",
     "Space selection": "Space selection",
     "Add existing rooms": "Add existing rooms",
     "Want to add a new room instead?": "Want to add a new room instead?",
     "Create a new room": "Create a new room",
+    "Search for rooms": "Search for rooms",
+    "Adding spaces has moved.": "Adding spaces has moved.",
     "Matrix ID": "Matrix ID",
     "Matrix Room ID": "Matrix Room ID",
     "email address": "email address",
@@ -2205,13 +2209,22 @@
     "Create a room in %(communityName)s": "Create a room in %(communityName)s",
     "Create a public room": "Create a public room",
     "Create a private room": "Create a private room",
+    "Topic (optional)": "Topic (optional)",
+    "Room visibility": "Room visibility",
     "Private room (invite only)": "Private room (invite only)",
     "Public room": "Public room",
     "Visible to space members": "Visible to space members",
-    "Topic (optional)": "Topic (optional)",
-    "Room visibility": "Room visibility",
     "Block anyone not part of %(serverName)s from ever joining this room.": "Block anyone not part of %(serverName)s from ever joining this room.",
     "Create Room": "Create Room",
+    "Anyone in <SpaceName/> will be able to find and join.": "Anyone in <SpaceName/> will be able to find and join.",
+    "Anyone will be able to find and join this space, not just members of <SpaceName/>.": "Anyone will be able to find and join this space, not just members of <SpaceName/>.",
+    "Only people invited will be able to find and join this space.": "Only people invited will be able to find and join this space.",
+    "Add a space to a space you manage.": "Add a space to a space you manage.",
+    "Space visibility": "Space visibility",
+    "Private space (invite only)": "Private space (invite only)",
+    "Public space": "Public space",
+    "Want to add an existing space instead?": "Want to add an existing space instead?",
+    "Adding...": "Adding...",
     "Sign out": "Sign out",
     "To avoid losing your chat history, you must export your room keys before logging out. You will need to go back to the newer version of %(brand)s to do this": "To avoid losing your chat history, you must export your room keys before logging out. You will need to go back to the newer version of %(brand)s to do this",
     "You've previously used a newer version of %(brand)s with this session. To use this version again with end to end encryption, you will need to sign out and back in again.": "You've previously used a newer version of %(brand)s with this session. To use this version again with end to end encryption, you will need to sign out and back in again.",
@@ -2803,7 +2816,6 @@
     "Search names and descriptions": "Search names and descriptions",
     "If you can't find the room you're looking for, ask for an invite or <a>create a new room</a>.": "If you can't find the room you're looking for, ask for an invite or <a>create a new room</a>.",
     "Create room": "Create room",
-    "Public space": "Public space",
     "Private space": "Private space",
     "<inviter/> invites you": "<inviter/> invites you",
     "To view %(spaceName)s, turn on the <a>Spaces beta</a>": "To view %(spaceName)s, turn on the <a>Spaces beta</a>",
@@ -2818,6 +2830,7 @@
     "Creating rooms...": "Creating rooms...",
     "What do you want to organise?": "What do you want to organise?",
     "Pick rooms or conversations to add. This is just a space for you, no one will be informed. You can add more later.": "Pick rooms or conversations to add. This is just a space for you, no one will be informed. You can add more later.",
+    "Search for rooms or spaces": "Search for rooms or spaces",
     "Share %(name)s": "Share %(name)s",
     "It's just you at the moment, it will be even better with others.": "It's just you at the moment, it will be even better with others.",
     "Go to my first room": "Go to my first room",

src/utils/space.tsx

@@ -28,6 +28,11 @@ import { _t } from "../languageHandler";
 import SpacePublicShare from "../components/views/spaces/SpacePublicShare";
 import InfoDialog from "../components/views/dialogs/InfoDialog";
 import { showRoomInviteDialog } from "../RoomInvite";
+import CreateSubspaceDialog from "../components/views/dialogs/CreateSubspaceDialog";
+import AddExistingSubspaceDialog from "../components/views/dialogs/AddExistingSubspaceDialog";
+import defaultDispatcher from "../dispatcher/dispatcher";
+import RoomViewStore from "../stores/RoomViewStore";
+import { Action } from "../dispatcher/actions";
 
 export const shouldShowSpaceSettings = (space: Room) => {
     const userId = space.client.getUserId();
@@ -54,21 +59,26 @@ export const showSpaceSettings = (space: Room) => {
     }, /*className=*/null, /*isPriority=*/false, /*isStatic=*/true);
 };
 
-export const showAddExistingRooms = async (space: Room) => {
+export const showAddExistingRooms = (space: Room): void => {
-    return Modal.createTrackedDialog(
+    Modal.createTrackedDialog(
         "Space Landing",
         "Add Existing",
         AddExistingToSpaceDialog,
         {
-            matrixClient: space.client,
+            onCreateRoomClick: () => showCreateNewRoom(space),
-            onCreateRoomClick: showCreateNewRoom,
+            onAddSubspaceClick: () => showAddExistingSubspace(space),
             space,
+            onFinished: (added: boolean) => {
+                if (added && RoomViewStore.getRoomId() === space.roomId) {
+                    defaultDispatcher.fire(Action.UpdateSpaceHierarchy);
+                }
+            },
         },
         "mx_AddExistingToSpaceDialog_wrapper",
-    ).finished;
+    );
 };
 
-export const showCreateNewRoom = async (space: Room) => {
+export const showCreateNewRoom = async (space: Room): Promise<boolean> => {
     const modal = Modal.createTrackedDialog<[boolean, IOpts]>(
         "Space Landing",
         "Create Room",
@@ -85,7 +95,7 @@ export const showCreateNewRoom = async (space: Room) => {
     return shouldCreate;
 };
 
-export const showSpaceInvite = (space: Room, initialText = "") => {
+export const showSpaceInvite = (space: Room, initialText = ""): void => {
     if (space.getJoinRule() === "public") {
         const modal = Modal.createTrackedDialog("Space Invite", "User Menu", InfoDialog, {
             title: _t("Invite to %(spaceName)s", { spaceName: space.name }),
@@ -102,3 +112,39 @@ export const showSpaceInvite = (space: Room, initialText = "") => {
         showRoomInviteDialog(space.roomId, initialText);
     }
 };
+
+export const showAddExistingSubspace = (space: Room): void => {
+    Modal.createTrackedDialog(
+        "Space Landing",
+        "Create Subspace",
+        AddExistingSubspaceDialog,
+        {
+            space,
+            onCreateSubspaceClick: () => showCreateNewSubspace(space),
+            onFinished: (added: boolean) => {
+                if (added && RoomViewStore.getRoomId() === space.roomId) {
+                    defaultDispatcher.fire(Action.UpdateSpaceHierarchy);
+                }
+            },
+        },
+        "mx_AddExistingToSpaceDialog_wrapper",
+    );
+};
+
+export const showCreateNewSubspace = (space: Room): void => {
+    Modal.createTrackedDialog(
+        "Space Landing",
+        "Create Subspace",
+        CreateSubspaceDialog,
+        {
+            space,
+            onAddExistingSpaceClick: () => showAddExistingSubspace(space),
+            onFinished: (added: boolean) => {
+                if (added && RoomViewStore.getRoomId() === space.roomId) {
+                    defaultDispatcher.fire(Action.UpdateSpaceHierarchy);
+                }
+            },
+        },
+        "mx_CreateSubspaceDialog_wrapper",
+    );
+};