diff --git a/package.json b/package.json
index 2df1926c8a..f658bf04b6 100644
--- a/package.json
+++ b/package.json
@@ -72,7 +72,7 @@
     },
     "dependencies": {
         "@babel/runtime": "^7.12.5",
-        "@matrix-org/analytics-events": "^0.25.0",
+        "@matrix-org/analytics-events": "^0.26.0",
         "@matrix-org/emojibase-bindings": "^1.1.2",
         "@matrix-org/matrix-wysiwyg": "2.37.9",
         "@matrix-org/react-sdk-module-api": "^2.4.0",
diff --git a/playwright/snapshots/crypto/crypto.spec.ts/RoomSummaryCard-with-verified-e2ee-linux.png b/playwright/snapshots/crypto/crypto.spec.ts/RoomSummaryCard-with-verified-e2ee-linux.png
index a8813b601d..3e68415017 100644
Binary files a/playwright/snapshots/crypto/crypto.spec.ts/RoomSummaryCard-with-verified-e2ee-linux.png and b/playwright/snapshots/crypto/crypto.spec.ts/RoomSummaryCard-with-verified-e2ee-linux.png differ
diff --git a/playwright/snapshots/pinned-messages/pinned-messages.spec.ts/pinned-messages-list-empty-linux.png b/playwright/snapshots/pinned-messages/pinned-messages.spec.ts/pinned-messages-list-empty-linux.png
index 38285305f6..16c694de95 100644
Binary files a/playwright/snapshots/pinned-messages/pinned-messages.spec.ts/pinned-messages-list-empty-linux.png and b/playwright/snapshots/pinned-messages/pinned-messages.spec.ts/pinned-messages-list-empty-linux.png differ
diff --git a/playwright/snapshots/polls/polls.spec.ts/ThreadView-with-a-poll-on-bubble-layout-linux.png b/playwright/snapshots/polls/polls.spec.ts/ThreadView-with-a-poll-on-bubble-layout-linux.png
index d35ec837b1..9a38579e21 100644
Binary files a/playwright/snapshots/polls/polls.spec.ts/ThreadView-with-a-poll-on-bubble-layout-linux.png and b/playwright/snapshots/polls/polls.spec.ts/ThreadView-with-a-poll-on-bubble-layout-linux.png differ
diff --git a/playwright/snapshots/polls/polls.spec.ts/ThreadView-with-a-poll-on-group-layout-linux.png b/playwright/snapshots/polls/polls.spec.ts/ThreadView-with-a-poll-on-group-layout-linux.png
index 0dfeb20b6a..f5bc02ef1e 100644
Binary files a/playwright/snapshots/polls/polls.spec.ts/ThreadView-with-a-poll-on-group-layout-linux.png and b/playwright/snapshots/polls/polls.spec.ts/ThreadView-with-a-poll-on-group-layout-linux.png differ
diff --git a/playwright/snapshots/right-panel/file-panel.spec.ts/empty-linux.png b/playwright/snapshots/right-panel/file-panel.spec.ts/empty-linux.png
index 178acd1828..9edd65a633 100644
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diff --git a/playwright/snapshots/right-panel/file-panel.spec.ts/file-tiles-list-linux.png b/playwright/snapshots/right-panel/file-panel.spec.ts/file-tiles-list-linux.png
index c5bf1e7d6a..0593b44155 100644
Binary files a/playwright/snapshots/right-panel/file-panel.spec.ts/file-tiles-list-linux.png and b/playwright/snapshots/right-panel/file-panel.spec.ts/file-tiles-list-linux.png differ
diff --git a/playwright/snapshots/right-panel/notification-panel.spec.ts/empty-linux.png b/playwright/snapshots/right-panel/notification-panel.spec.ts/empty-linux.png
index b80b57fe4b..26481bfe5d 100644
Binary files a/playwright/snapshots/right-panel/notification-panel.spec.ts/empty-linux.png and b/playwright/snapshots/right-panel/notification-panel.spec.ts/empty-linux.png differ
diff --git a/playwright/snapshots/right-panel/right-panel.spec.ts/with-name-and-address-linux.png b/playwright/snapshots/right-panel/right-panel.spec.ts/with-name-and-address-linux.png
index 68f31135c5..4e3c67393b 100644
Binary files a/playwright/snapshots/right-panel/right-panel.spec.ts/with-name-and-address-linux.png and b/playwright/snapshots/right-panel/right-panel.spec.ts/with-name-and-address-linux.png differ
diff --git a/playwright/snapshots/threads/threads.spec.ts/Reply-to-the-location-on-ThreadView-linux.png b/playwright/snapshots/threads/threads.spec.ts/Reply-to-the-location-on-ThreadView-linux.png
index 32950f4dde..4652833628 100644
Binary files a/playwright/snapshots/threads/threads.spec.ts/Reply-to-the-location-on-ThreadView-linux.png and b/playwright/snapshots/threads/threads.spec.ts/Reply-to-the-location-on-ThreadView-linux.png differ
diff --git a/playwright/snapshots/timeline/timeline.spec.ts/highlighted-search-results-linux.png b/playwright/snapshots/timeline/timeline.spec.ts/highlighted-search-results-linux.png
index 347c7a5477..008ebc82e3 100644
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diff --git a/playwright/snapshots/timeline/timeline.spec.ts/search-aux-panel-linux.png b/playwright/snapshots/timeline/timeline.spec.ts/search-aux-panel-linux.png
index fe96a9e6be..b50f176222 100644
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diff --git a/playwright/snapshots/timeline/timeline.spec.ts/search-results-with-TextualEvent-linux.png b/playwright/snapshots/timeline/timeline.spec.ts/search-results-with-TextualEvent-linux.png
index c1d762d512..cf489b1836 100644
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diff --git a/playwright/snapshots/user-view/user-view.spec.ts/user-info-linux.png b/playwright/snapshots/user-view/user-view.spec.ts/user-info-linux.png
index 6e4df5c776..0612fe1ba7 100644
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diff --git a/src/components/structures/MainSplit.tsx b/src/components/structures/MainSplit.tsx
index 282ec69e18..54aa220354 100644
--- a/src/components/structures/MainSplit.tsx
+++ b/src/components/structures/MainSplit.tsx
@@ -10,8 +10,10 @@ Please see LICENSE files in the repository root for full details.
 import React, { ReactNode } from "react";
 import { NumberSize, Resizable } from "re-resizable";
 import { Direction } from "re-resizable/lib/resizer";
+import { WebPanelResize } from "@matrix-org/analytics-events/types/typescript/WebPanelResize";
 
 import ResizeNotifier from "../../utils/ResizeNotifier";
+import { PosthogAnalytics } from "../../PosthogAnalytics.ts";
 
 interface IProps {
     resizeNotifier: ResizeNotifier;
@@ -26,14 +28,16 @@ interface IProps {
      */
     sizeKey?: string;
     /**
-     * The size to use for the panel component if one isn't persisted in storage. Defaults to 350.
+     * The size to use for the panel component if one isn't persisted in storage. Defaults to 320.
      */
     defaultSize: number;
+
+    analyticsRoomType: WebPanelResize["roomType"];
 }
 
 export default class MainSplit extends React.Component<IProps> {
     public static defaultProps = {
-        defaultSize: 350,
+        defaultSize: 320,
     };
 
     private onResizeStart = (): void => {
@@ -58,11 +62,16 @@ export default class MainSplit extends React.Component<IProps> {
         elementRef: HTMLElement,
         delta: NumberSize,
     ): void => {
+        const newSize = this.loadSidePanelSize().width + delta.width;
         this.props.resizeNotifier.stopResizing();
-        window.localStorage.setItem(
-            this.sizeSettingStorageKey,
-            (this.loadSidePanelSize().width + delta.width).toString(),
-        );
+        window.localStorage.setItem(this.sizeSettingStorageKey, newSize.toString());
+
+        PosthogAnalytics.instance.trackEvent<WebPanelResize>({
+            eventName: "WebPanelResize",
+            panel: "right",
+            roomType: this.props.analyticsRoomType,
+            size: newSize,
+        });
     };
 
     private loadSidePanelSize(): { height: string | number; width: number } {
diff --git a/src/components/structures/RoomView.tsx b/src/components/structures/RoomView.tsx
index ba30a3445d..958c93bebc 100644
--- a/src/components/structures/RoomView.tsx
+++ b/src/components/structures/RoomView.tsx
@@ -9,7 +9,7 @@ SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only
 Please see LICENSE files in the repository root for full details.
 */
 
-import React, { ChangeEvent, createRef, ReactElement, ReactNode, RefObject, useContext } from "react";
+import React, { ChangeEvent, ComponentProps, createRef, ReactElement, ReactNode, RefObject, useContext } from "react";
 import classNames from "classnames";
 import {
     IRecommendedVersion,
@@ -54,7 +54,7 @@ import WidgetEchoStore from "../../stores/WidgetEchoStore";
 import SettingsStore from "../../settings/SettingsStore";
 import { Layout } from "../../settings/enums/Layout";
 import AccessibleButton, { ButtonEvent } from "../views/elements/AccessibleButton";
-import RoomContext, { TimelineRenderingType } from "../../contexts/RoomContext";
+import RoomContext, { TimelineRenderingType, MainSplitContentType } from "../../contexts/RoomContext";
 import { E2EStatus, shieldStatusForRoom } from "../../utils/ShieldUtils";
 import { Action } from "../../dispatcher/actions";
 import { IMatrixClientCreds } from "../../MatrixClientPeg";
@@ -152,13 +152,8 @@ interface IRoomProps {
     onRegistered?(credentials: IMatrixClientCreds): void;
 }
 
-// This defines the content of the mainSplit.
-// If the mainSplit does not contain the Timeline, the chat is shown in the right panel.
-export enum MainSplitContentType {
-    Timeline,
-    MaximisedWidget,
-    Call,
-}
+export { MainSplitContentType };
+
 export interface IRoomState {
     room?: Room;
     virtualRoom?: Room;
@@ -191,11 +186,6 @@ export interface IRoomState {
     showApps: boolean;
     isPeeking: boolean;
     showRightPanel: boolean;
-    /**
-     * Whether the right panel shown is either of ThreadPanel or ThreadView.
-     * Always false when `showRightPanel` is false.
-     */
-    threadRightPanel: boolean;
     // error object, as from the matrix client/server API
     // If we failed to load information about the room,
     // store the error here.
@@ -234,7 +224,7 @@ export interface IRoomState {
     e2eStatus?: E2EStatus;
     rejecting?: boolean;
     hasPinnedWidgets?: boolean;
-    mainSplitContentType?: MainSplitContentType;
+    mainSplitContentType: MainSplitContentType;
     // whether or not a spaces context switch brought us here,
     // if it did we don't want the room to be marked as read as soon as it is loaded.
     wasContextSwitch?: boolean;
@@ -399,7 +389,6 @@ export class RoomView extends React.Component<IRoomProps, IRoomState> {
             showApps: false,
             isPeeking: false,
             showRightPanel: false,
-            threadRightPanel: false,
             joining: false,
             showTopUnreadMessagesBar: false,
             statusBarVisible: false,
@@ -626,11 +615,6 @@ export class RoomView extends React.Component<IRoomProps, IRoomState> {
             mainSplitContentType: room ? this.getMainSplitContentType(room) : undefined,
             initialEventId: undefined, // default to clearing this, will get set later in the method if needed
             showRightPanel: roomId ? this.context.rightPanelStore.isOpenForRoom(roomId) : false,
-            threadRightPanel: roomId
-                ? [RightPanelPhases.ThreadView, RightPanelPhases.ThreadPanel].includes(
-                      this.context.rightPanelStore.currentCardForRoom(roomId).phase!,
-                  )
-                : false,
             activeCall: roomId ? CallStore.instance.getActiveCall(roomId) : null,
             promptAskToJoin: this.context.roomViewStore.promptAskToJoin(),
             viewRoomOpts: this.context.roomViewStore.getViewRoomOpts(),
@@ -1033,11 +1017,6 @@ export class RoomView extends React.Component<IRoomProps, IRoomState> {
         const { roomId } = this.state;
         this.setState({
             showRightPanel: roomId ? this.context.rightPanelStore.isOpenForRoom(roomId) : false,
-            threadRightPanel: roomId
-                ? [RightPanelPhases.ThreadView, RightPanelPhases.ThreadPanel].includes(
-                      this.context.rightPanelStore.currentCardForRoom(roomId).phase!,
-                  )
-                : false,
         });
     };
 
@@ -2531,6 +2510,17 @@ export class RoomView extends React.Component<IRoomProps, IRoomState> {
         }
         const mainSplitContentClasses = classNames("mx_RoomView_body", mainSplitContentClassName);
 
+        let sizeKey: string | undefined;
+        let defaultSize: number | undefined;
+        let analyticsRoomType: ComponentProps<typeof MainSplit>["analyticsRoomType"] = "other_room";
+        if (this.state.mainSplitContentType !== MainSplitContentType.Timeline) {
+            // Override defaults for video rooms where more space is needed for the chat timeline
+            sizeKey = "wide";
+            defaultSize = 420;
+            analyticsRoomType =
+                this.state.mainSplitContentType === MainSplitContentType.Call ? "video_room" : "maximised_widget";
+        }
+
         return (
             <RoomContext.Provider value={this.state}>
                 <div className={mainClasses} ref={this.roomView} onKeyDown={this.onReactKeyDown}>
@@ -2541,10 +2531,9 @@ export class RoomView extends React.Component<IRoomProps, IRoomState> {
                         <MainSplit
                             panel={rightPanel}
                             resizeNotifier={this.props.resizeNotifier}
-                            // Override defaults when a thread is being shown to allow persisting a separate
-                            // right panel width for thread panels as they tend to want to be wider.
-                            sizeKey={this.state.threadRightPanel ? "thread" : undefined}
-                            defaultSize={this.state.threadRightPanel ? 500 : undefined}
+                            sizeKey={sizeKey}
+                            defaultSize={defaultSize}
+                            analyticsRoomType={analyticsRoomType}
                         >
                             <div
                                 className={mainSplitContentClasses}
diff --git a/src/components/structures/SpaceRoomView.tsx b/src/components/structures/SpaceRoomView.tsx
index 8bf1cc4580..4f0c895233 100644
--- a/src/components/structures/SpaceRoomView.tsx
+++ b/src/components/structures/SpaceRoomView.tsx
@@ -764,7 +764,7 @@ export default class SpaceRoomView extends React.PureComponent<IProps, IState> {
         return (
             <main className="mx_SpaceRoomView">
                 <ErrorBoundary>
-                    <MainSplit panel={rightPanel} resizeNotifier={this.props.resizeNotifier}>
+                    <MainSplit panel={rightPanel} resizeNotifier={this.props.resizeNotifier} analyticsRoomType="space">
                         {this.renderBody()}
                     </MainSplit>
                 </ErrorBoundary>
diff --git a/src/components/structures/UserView.tsx b/src/components/structures/UserView.tsx
index 4647c24b26..635115877e 100644
--- a/src/components/structures/UserView.tsx
+++ b/src/components/structures/UserView.tsx
@@ -87,7 +87,12 @@ export default class UserView extends React.Component<IProps, IState> {
                 />
             );
             return (
-                <MainSplit panel={panel} resizeNotifier={this.props.resizeNotifier}>
+                <MainSplit
+                    panel={panel}
+                    resizeNotifier={this.props.resizeNotifier}
+                    defaultSize={420}
+                    analyticsRoomType="user_profile"
+                >
                     <UserOnboardingPage />
                 </MainSplit>
             );
diff --git a/src/contexts/RoomContext.ts b/src/contexts/RoomContext.ts
index 8fb94a245d..acd4bfa6f4 100644
--- a/src/contexts/RoomContext.ts
+++ b/src/contexts/RoomContext.ts
@@ -21,6 +21,14 @@ export enum TimelineRenderingType {
     Pinned = "Pinned",
 }
 
+// This defines the content of the mainSplit.
+// If the mainSplit does not contain the Timeline, the chat is shown in the right panel.
+export enum MainSplitContentType {
+    Timeline,
+    MaximisedWidget,
+    Call,
+}
+
 const RoomContext = createContext<
     IRoomState & {
         threadId?: string;
@@ -35,7 +43,6 @@ const RoomContext = createContext<
     showApps: false,
     isPeeking: false,
     showRightPanel: true,
-    threadRightPanel: false,
     joining: false,
     showTopUnreadMessagesBar: false,
     statusBarVisible: false,
@@ -59,6 +66,7 @@ const RoomContext = createContext<
     matrixClientIsReady: false,
     showUrlPreview: false,
     timelineRenderingType: TimelineRenderingType.Room,
+    mainSplitContentType: MainSplitContentType.Timeline,
     threadId: undefined,
     liveTimeline: undefined,
     narrow: false,
diff --git a/test/components/structures/MainSplit-test.tsx b/test/components/structures/MainSplit-test.tsx
index 28152fefa2..6dbc733075 100644
--- a/test/components/structures/MainSplit-test.tsx
+++ b/test/components/structures/MainSplit-test.tsx
@@ -7,10 +7,11 @@ Please see LICENSE files in the repository root for full details.
 */
 
 import React from "react";
-import { render } from "@testing-library/react";
+import { fireEvent, render } from "@testing-library/react";
 
 import MainSplit from "../../../src/components/structures/MainSplit";
 import ResizeNotifier from "../../../src/utils/ResizeNotifier";
+import { PosthogAnalytics } from "../../../src/PosthogAnalytics.ts";
 
 describe("<MainSplit/>", () => {
     const resizeNotifier = new ResizeNotifier();
@@ -21,18 +22,33 @@ describe("<MainSplit/>", () => {
     );
     const panel = <div>Right panel</div>;
 
+    beforeEach(() => {
+        localStorage.clear();
+    });
+
     it("renders", () => {
         const { asFragment, container } = render(
-            <MainSplit resizeNotifier={resizeNotifier} children={children} panel={panel} />,
+            <MainSplit
+                resizeNotifier={resizeNotifier}
+                children={children}
+                panel={panel}
+                analyticsRoomType="other_room"
+            />,
         );
         expect(asFragment()).toMatchSnapshot();
-        // Assert it matches the default width of 350
-        expect(container.querySelector<HTMLElement>(".mx_RightPanel_ResizeWrapper")!.style.width).toBe("350px");
+        // Assert it matches the default width of 320
+        expect(container.querySelector<HTMLElement>(".mx_RightPanel_ResizeWrapper")!.style.width).toBe("320px");
     });
 
     it("respects defaultSize prop", () => {
         const { asFragment, container } = render(
-            <MainSplit resizeNotifier={resizeNotifier} children={children} panel={panel} defaultSize={500} />,
+            <MainSplit
+                resizeNotifier={resizeNotifier}
+                children={children}
+                panel={panel}
+                defaultSize={500}
+                analyticsRoomType="other_room"
+            />,
         );
         expect(asFragment()).toMatchSnapshot();
         // Assert it matches the default width of 350
@@ -48,8 +64,36 @@ describe("<MainSplit/>", () => {
                 panel={panel}
                 sizeKey="thread"
                 defaultSize={400}
+                analyticsRoomType="other_room"
             />,
         );
         expect(container.querySelector<HTMLElement>(".mx_RightPanel_ResizeWrapper")!.style.width).toBe("333px");
     });
+
+    it("should report to analytics on resize stop", () => {
+        const { container } = render(
+            <MainSplit
+                resizeNotifier={resizeNotifier}
+                children={children}
+                panel={panel}
+                sizeKey="thread"
+                defaultSize={400}
+                analyticsRoomType="other_room"
+            />,
+        );
+
+        const spy = jest.spyOn(PosthogAnalytics.instance, "trackEvent");
+
+        const handle = container.querySelector(".mx_ResizeHandle--horizontal")!;
+        fireEvent.mouseDown(handle);
+        fireEvent.mouseMove(handle, { clientX: 0 });
+        fireEvent.mouseUp(handle);
+
+        expect(spy).toHaveBeenCalledWith({
+            eventName: "WebPanelResize",
+            panel: "right",
+            roomType: "other_room",
+            size: 400,
+        });
+    });
 });
diff --git a/test/components/structures/RoomView-test.tsx b/test/components/structures/RoomView-test.tsx
index e1dad1cb9d..1e11272c56 100644
--- a/test/components/structures/RoomView-test.tsx
+++ b/test/components/structures/RoomView-test.tsx
@@ -311,6 +311,12 @@ describe("RoomView", () => {
             expect(stores.rightPanelStore.isOpen).toEqual(true);
             expect(stores.rightPanelStore.currentCard.phase).toEqual(RightPanelPhases.Timeline);
         });
+
+        it("should render joined video room view", async () => {
+            jest.spyOn(room, "getMyMembership").mockReturnValue(KnownMembership.Join);
+            const { asFragment } = await mountRoomView();
+            expect(asFragment()).toMatchSnapshot();
+        });
     });
 
     describe("for a local room", () => {
diff --git a/test/components/structures/__snapshots__/MainSplit-test.tsx.snap b/test/components/structures/__snapshots__/MainSplit-test.tsx.snap
index d6cd201594..94f5b23604 100644
--- a/test/components/structures/__snapshots__/MainSplit-test.tsx.snap
+++ b/test/components/structures/__snapshots__/MainSplit-test.tsx.snap
@@ -14,7 +14,7 @@ exports[`<MainSplit/> renders 1`] = `
     </div>
     <div
       class="mx_RightPanel_ResizeWrapper"
-      style="position: relative; user-select: auto; width: 350px; height: 100%; max-width: 50%; min-width: 264px; box-sizing: border-box; flex-shrink: 0;"
+      style="position: relative; user-select: auto; width: 320px; height: 100%; max-width: 50%; min-width: 264px; box-sizing: border-box; flex-shrink: 0;"
     >
       <div>
         Right panel
diff --git a/test/components/structures/__snapshots__/RoomView-test.tsx.snap b/test/components/structures/__snapshots__/RoomView-test.tsx.snap
index 25740fbd0b..f6a79b6cd7 100644
--- a/test/components/structures/__snapshots__/RoomView-test.tsx.snap
+++ b/test/components/structures/__snapshots__/RoomView-test.tsx.snap
@@ -1125,3 +1125,322 @@ exports[`RoomView should show error view if failed to look up room alias 1`] = `
   </div>
 </DocumentFragment>
 `;
+
+exports[`RoomView video rooms should render joined video room view 1`] = `
+<DocumentFragment>
+  <div
+    class="mx_RoomView mx_RoomView_immersive"
+  >
+    <canvas
+      aria-hidden="true"
+      height="768"
+      style="display: block; z-index: 999999; pointer-events: none; position: fixed; top: 0px; right: 0px;"
+      width="0"
+    />
+    <div
+      class="mx_MainSplit"
+    >
+      <div
+        class="mx_RoomView_body mx_MainSplit_call"
+        data-layout="group"
+      >
+        <header
+          class="mx_Flex mx_RoomHeader light-panel"
+          style="--mx-flex-display: flex; --mx-flex-direction: row; --mx-flex-align: center; --mx-flex-justify: start; --mx-flex-gap: var(--cpd-space-3x);"
+        >
+          <button
+            aria-label="Open room settings"
+            aria-live="off"
+            class="_avatar_mcap2_17 mx_BaseAvatar _avatar-imageless_mcap2_61"
+            data-color="3"
+            data-testid="avatar-img"
+            data-type="round"
+            role="button"
+            style="--cpd-avatar-size: 40px;"
+            tabindex="-1"
+          >
+            !
+          </button>
+          <button
+            aria-label="Room info"
+            class="mx_RoomHeader_infoWrapper"
+            tabindex="0"
+          >
+            <div
+              class="mx_Box mx_RoomHeader_info mx_Box--flex"
+              style="--mx-box-flex: 1;"
+            >
+              <div
+                aria-level="1"
+                class="_typography_yh5dq_162 _font-body-lg-semibold_yh5dq_83 mx_RoomHeader_heading"
+                dir="auto"
+                role="heading"
+              >
+                <span
+                  class="mx_RoomHeader_truncated mx_lineClamp"
+                >
+                  !10:example.org
+                </span>
+              </div>
+            </div>
+          </button>
+          <div
+            class="mx_Flex"
+            style="--mx-flex-display: flex; --mx-flex-direction: row; --mx-flex-align: center; --mx-flex-justify: start; --mx-flex-gap: var(--cpd-space-2x);"
+          >
+            <button
+              aria-label="Room info"
+              class="_icon-button_bh2qc_17"
+              role="button"
+              style="--cpd-icon-button-size: 32px;"
+              tabindex="0"
+            >
+              <div
+                class="_indicator-icon_133tf_26"
+                style="--cpd-icon-button-size: 100%;"
+              >
+                <div />
+              </div>
+            </button>
+            <button
+              aria-label="Chat"
+              class="_icon-button_bh2qc_17"
+              role="button"
+              style="--cpd-icon-button-size: 32px;"
+              tabindex="0"
+            >
+              <div
+                class="_indicator-icon_133tf_26"
+                style="--cpd-icon-button-size: 100%;"
+              >
+                <div />
+              </div>
+            </button>
+            <button
+              aria-label="Threads"
+              class="_icon-button_bh2qc_17"
+              role="button"
+              style="--cpd-icon-button-size: 32px;"
+              tabindex="0"
+            >
+              <div
+                class="_indicator-icon_133tf_26"
+                style="--cpd-icon-button-size: 100%;"
+              >
+                <div />
+              </div>
+            </button>
+          </div>
+          <div
+            class="_typography_yh5dq_162 _font-body-sm-medium_yh5dq_50"
+          >
+            <div
+              aria-label="0 members"
+              class="mx_AccessibleButton mx_FacePile"
+              role="button"
+              tabindex="0"
+            >
+              <div
+                class="_stacked-avatars_mcap2_111"
+              />
+              0
+            </div>
+          </div>
+        </header>
+      </div>
+      <div
+        class="mx_RightPanel_ResizeWrapper"
+        style="position: relative; user-select: auto; width: 420px; height: 100%; max-width: 50%; min-width: 264px; box-sizing: border-box; flex-shrink: 0;"
+      >
+        <aside
+          class="mx_RightPanel"
+          id="mx_RightPanel"
+        >
+          <div
+            class="mx_BaseCard mx_ThreadPanel mx_TimelineCard"
+          >
+            <div
+              class="mx_BaseCard_header"
+            >
+              <div
+                class="mx_BaseCard_header_title"
+              >
+                <p
+                  class="_typography_yh5dq_162 _font-body-md-medium_yh5dq_69 mx_BaseCard_header_title_heading"
+                  role="heading"
+                >
+                  Chat
+                </p>
+              </div>
+              <button
+                class="_icon-button_bh2qc_17 _subtle-bg_bh2qc_38"
+                data-testid="base-card-close-button"
+                role="button"
+                style="--cpd-icon-button-size: 28px;"
+                tabindex="0"
+              >
+                <div
+                  class="_indicator-icon_133tf_26"
+                  style="--cpd-icon-button-size: 100%;"
+                >
+                  <svg
+                    fill="currentColor"
+                    height="1em"
+                    viewBox="0 0 24 24"
+                    width="1em"
+                    xmlns="http://www.w3.org/2000/svg"
+                  >
+                    <path
+                      d="M6.293 6.293a1 1 0 0 1 1.414 0L12 10.586l4.293-4.293a1 1 0 1 1 1.414 1.414L13.414 12l4.293 4.293a1 1 0 0 1-1.414 1.414L12 13.414l-4.293 4.293a1 1 0 0 1-1.414-1.414L10.586 12 6.293 7.707a1 1 0 0 1 0-1.414Z"
+                    />
+                  </svg>
+                </div>
+              </button>
+            </div>
+            <div
+              class="mx_TimelineCard_timeline"
+            >
+              <div
+                class="mx_AutoHideScrollbar mx_ScrollPanel mx_RoomView_messagePanel"
+                tabindex="-1"
+              >
+                <div
+                  class="mx_RoomView_messageListWrapper"
+                >
+                  <ol
+                    aria-live="polite"
+                    class="mx_RoomView_MessageList"
+                    style="height: 400px;"
+                  />
+                </div>
+              </div>
+            </div>
+            <div
+              aria-label="Message composer"
+              class="mx_MessageComposer mx_MessageComposer--compact"
+              role="region"
+            >
+              <div
+                class="mx_MessageComposer_wrapper"
+              >
+                <div
+                  class="mx_MessageComposer_row"
+                >
+                  <div
+                    class="mx_SendMessageComposer"
+                  >
+                    <div
+                      class="mx_BasicMessageComposer"
+                    >
+                      <div
+                        aria-label="Formatting"
+                        class="mx_MessageComposerFormatBar"
+                        role="toolbar"
+                      >
+                        <button
+                          aria-label="Bold"
+                          class="mx_AccessibleButton mx_MessageComposerFormatBar_button mx_MessageComposerFormatBar_buttonIconBold"
+                          role="button"
+                          tabindex="0"
+                          type="button"
+                        />
+                        <button
+                          aria-label="Italics"
+                          class="mx_AccessibleButton mx_MessageComposerFormatBar_button mx_MessageComposerFormatBar_buttonIconItalic"
+                          role="button"
+                          tabindex="-1"
+                          type="button"
+                        />
+                        <button
+                          aria-label="Strikethrough"
+                          class="mx_AccessibleButton mx_MessageComposerFormatBar_button mx_MessageComposerFormatBar_buttonIconStrikethrough"
+                          role="button"
+                          tabindex="-1"
+                          type="button"
+                        />
+                        <button
+                          aria-label="Code block"
+                          class="mx_AccessibleButton mx_MessageComposerFormatBar_button mx_MessageComposerFormatBar_buttonIconCode"
+                          role="button"
+                          tabindex="-1"
+                          type="button"
+                        />
+                        <button
+                          aria-label="Quote"
+                          class="mx_AccessibleButton mx_MessageComposerFormatBar_button mx_MessageComposerFormatBar_buttonIconQuote"
+                          role="button"
+                          tabindex="-1"
+                          type="button"
+                        />
+                        <button
+                          aria-label="Insert link"
+                          class="mx_AccessibleButton mx_MessageComposerFormatBar_button mx_MessageComposerFormatBar_buttonIconInsertLink"
+                          role="button"
+                          tabindex="-1"
+                          type="button"
+                        />
+                      </div>
+                      <div
+                        aria-autocomplete="list"
+                        aria-disabled="false"
+                        aria-haspopup="listbox"
+                        aria-label="Send a message…"
+                        aria-multiline="true"
+                        class="mx_BasicMessageComposer_input mx_BasicMessageComposer_input_shouldShowPillAvatar mx_BasicMessageComposer_inputEmpty"
+                        contenteditable="true"
+                        data-testid="basicmessagecomposer"
+                        dir="auto"
+                        role="textbox"
+                        style="--placeholder: 'Send\\ a\\ message…';"
+                        tabindex="0"
+                        translate="no"
+                      >
+                        <div>
+                          <br />
+                        </div>
+                      </div>
+                    </div>
+                  </div>
+                  <div
+                    class="mx_MessageComposer_actions"
+                  >
+                    <div
+                      aria-label="Emoji"
+                      class="mx_AccessibleButton mx_EmojiButton mx_MessageComposer_button mx_EmojiButton_icon"
+                      role="button"
+                      tabindex="0"
+                    />
+                    <div
+                      aria-label="Attachment"
+                      class="mx_AccessibleButton mx_MessageComposer_button mx_MessageComposer_upload"
+                      role="button"
+                      tabindex="0"
+                    />
+                    <div
+                      aria-label="More options"
+                      class="mx_AccessibleButton mx_MessageComposer_button mx_MessageComposer_buttonMenu"
+                      role="button"
+                      tabindex="0"
+                    />
+                    <input
+                      multiple=""
+                      style="display: none;"
+                      type="file"
+                    />
+                  </div>
+                </div>
+              </div>
+            </div>
+          </div>
+        </aside>
+        <div>
+          <div
+            class="mx_ResizeHandle--horizontal"
+            style="position: absolute; user-select: none; width: 10px; height: 100%; top: 0px; left: -5px; cursor: col-resize;"
+          />
+        </div>
+      </div>
+    </div>
+  </div>
+</DocumentFragment>
+`;
diff --git a/test/components/views/rooms/SendMessageComposer-test.tsx b/test/components/views/rooms/SendMessageComposer-test.tsx
index 11d887bd9d..562f8b26d8 100644
--- a/test/components/views/rooms/SendMessageComposer-test.tsx
+++ b/test/components/views/rooms/SendMessageComposer-test.tsx
@@ -26,7 +26,7 @@ import { MatrixClientPeg } from "../../../../src/MatrixClientPeg";
 import defaultDispatcher from "../../../../src/dispatcher/dispatcher";
 import DocumentOffset from "../../../../src/editor/offset";
 import { Layout } from "../../../../src/settings/enums/Layout";
-import { IRoomState } from "../../../../src/components/structures/RoomView";
+import { IRoomState, MainSplitContentType } from "../../../../src/components/structures/RoomView";
 import { RoomPermalinkCreator } from "../../../../src/utils/permalinks/Permalinks";
 import { mockPlatformPeg } from "../../../test-utils/platform";
 import { doMaybeLocalRoomAction } from "../../../../src/utils/local-room";
@@ -47,7 +47,6 @@ describe("<SendMessageComposer/>", () => {
         showApps: false,
         isPeeking: false,
         showRightPanel: true,
-        threadRightPanel: false,
         joining: false,
         atEndOfLiveTimeline: true,
         showTopUnreadMessagesBar: false,
@@ -69,6 +68,7 @@ describe("<SendMessageComposer/>", () => {
         showDisplaynameChanges: true,
         matrixClientIsReady: false,
         timelineRenderingType: TimelineRenderingType.Room,
+        mainSplitContentType: MainSplitContentType.Timeline,
         liveTimeline: undefined,
         canSelfRedact: false,
         resizing: false,
diff --git a/test/test-utils/room.ts b/test/test-utils/room.ts
index bf04985743..d618932726 100644
--- a/test/test-utils/room.ts
+++ b/test/test-utils/room.ts
@@ -7,10 +7,10 @@ Please see LICENSE files in the repository root for full details.
 */
 
 import { MockedObject } from "jest-mock";
-import { MatrixClient, MatrixEvent, EventType, Room, EventTimeline } from "matrix-js-sdk/src/matrix";
+import { EventTimeline, EventType, MatrixClient, MatrixEvent, Room } from "matrix-js-sdk/src/matrix";
 import { KnownMembership } from "matrix-js-sdk/src/types";
 
-import { IRoomState } from "../../src/components/structures/RoomView";
+import { IRoomState, MainSplitContentType } from "../../src/components/structures/RoomView";
 import { TimelineRenderingType } from "../../src/contexts/RoomContext";
 import { Layout } from "../../src/settings/enums/Layout";
 import { mkEvent } from "./test-utils";
@@ -54,7 +54,6 @@ export function getRoomContext(room: Room, override: Partial<IRoomState>): IRoom
         showApps: false,
         isPeeking: false,
         showRightPanel: true,
-        threadRightPanel: false,
         joining: false,
         atEndOfLiveTimeline: true,
         showTopUnreadMessagesBar: false,
@@ -76,6 +75,7 @@ export function getRoomContext(room: Room, override: Partial<IRoomState>): IRoom
         showDisplaynameChanges: true,
         matrixClientIsReady: false,
         timelineRenderingType: TimelineRenderingType.Room,
+        mainSplitContentType: MainSplitContentType.Timeline,
         liveTimeline: undefined,
         canSelfRedact: false,
         resizing: false,
diff --git a/yarn.lock b/yarn.lock
index 18a38788a5..ee422b6f28 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1893,10 +1893,10 @@
   resolved "https://registry.yarnpkg.com/@mapbox/whoots-js/-/whoots-js-3.1.0.tgz#497c67a1cef50d1a2459ba60f315e448d2ad87fe"
   integrity sha512-Es6WcD0nO5l+2BOQS4uLfNPYQaNDfbot3X1XUoloz+x0mPDS3eeORZJl06HXjwBG1fOGwCRnzK88LMdxKRrd6Q==
 
-"@matrix-org/analytics-events@^0.25.0":
-  version "0.25.0"
-  resolved "https://registry.yarnpkg.com/@matrix-org/analytics-events/-/analytics-events-0.25.0.tgz#b0b85297dc05a67feaf89cc5d70b80283c988141"
-  integrity sha512-UCTuMjlJGArMqG9qXGfeNz/XtZDFldwuO+dkqP6Wo1nVdWasoWAOlcimDWQ2JnNFCg+UDZU+HLBdS5juTd6xTg==
+"@matrix-org/analytics-events@^0.26.0":
+  version "0.26.0"
+  resolved "https://registry.yarnpkg.com/@matrix-org/analytics-events/-/analytics-events-0.26.0.tgz#7c8f8f924d8313c87951a0e941640ef8ff78f3d6"
+  integrity sha512-cjKZBejajUG8wPhVygMkBTwTLdEn74luUP6g6RjCUqPR3RYIl3NVi58Zil8CWfRTILb4wVLCPpAvehgXJn1HnQ==
 
 "@matrix-org/emojibase-bindings@^1.1.2":
   version "1.1.3"
@@ -9599,7 +9599,6 @@ which@^2.0.1:
     isexe "^2.0.0"
 
 "wrap-ansi-cjs@npm:wrap-ansi@^7.0.0":
-  name wrap-ansi-cjs
   version "7.0.0"
   resolved "https://registry.yarnpkg.com/wrap-ansi/-/wrap-ansi-7.0.0.tgz#67e145cff510a6a6984bdf1152911d69d2eb9e43"
   integrity sha512-YVGIj2kamLSTxw6NsZjoBxfSwsn0ycdesmc4p+Q21c5zPuZ1pl+NfxVdxPtdHvmNVOQ6XSYG4AUtyt/Fi7D16Q==