Put the right-click message context menu to the right (#8339)

* Improve `alwaysAboveRightOf()` typing

Signed-off-by: Šimon Brandner <simon.bra.ag@gmail.com>

* Improve typing of `alwaysAboveLeftOf()`

Signed-off-by: Šimon Brandner <simon.bra.ag@gmail.com>

* Add `aboveRightOf()`

Signed-off-by: Šimon Brandner <simon.bra.ag@gmail.com>

* Use `aboveRightOf()`

Signed-off-by: Šimon Brandner <simon.bra.ag@gmail.com>

* Fix typo

Signed-off-by: Šimon Brandner <simon.bra.ag@gmail.com>

src/components/structures/ContextMenu.tsx

@@ -450,9 +450,37 @@ export const aboveLeftOf = (
     return menuOptions;
 };
 
+// Placement method for <ContextMenu /> to position context menu right-aligned and flowing to the right of elementRect,
+// and either above or below: wherever there is more space (maybe this should be aboveOrBelowRightOf?)
+export const aboveRightOf = (
+    elementRect: Pick<DOMRect, "left" | "top" | "bottom">,
+    chevronFace = ChevronFace.None,
+    vPadding = 0,
+): AboveLeftOf => {
+    const menuOptions: IPosition & { chevronFace: ChevronFace } = { chevronFace };
+
+    const buttonLeft = elementRect.left + window.pageXOffset;
+    const buttonBottom = elementRect.bottom + window.pageYOffset;
+    const buttonTop = elementRect.top + window.pageYOffset;
+    // Align the left edge of the menu to the left edge of the button
+    menuOptions.left = buttonLeft;
+    // Align the menu vertically on whichever side of the button has more space available.
+    if (buttonBottom < UIStore.instance.windowHeight / 2) {
+        menuOptions.top = buttonBottom + vPadding;
+    } else {
+        menuOptions.bottom = (UIStore.instance.windowHeight - buttonTop) + vPadding;
+    }
+
+    return menuOptions;
+};
+
 // Placement method for <ContextMenu /> to position context menu right-aligned and flowing to the left of elementRect
 // and always above elementRect
-export const alwaysAboveLeftOf = (elementRect: DOMRect, chevronFace = ChevronFace.None, vPadding = 0) => {
+export const alwaysAboveLeftOf = (
+    elementRect: Pick<DOMRect, "right" | "bottom" | "top">,
+    chevronFace = ChevronFace.None,
+    vPadding = 0,
+) => {
     const menuOptions: IPosition & { chevronFace: ChevronFace } = { chevronFace };
 
     const buttonRight = elementRect.right + window.pageXOffset;
@@ -472,7 +500,11 @@ export const alwaysAboveLeftOf = (elementRect: DOMRect, chevronFace = ChevronFac
 
 // Placement method for <ContextMenu /> to position context menu right-aligned and flowing to the right of elementRect
 // and always above elementRect
-export const alwaysAboveRightOf = (elementRect: DOMRect, chevronFace = ChevronFace.None, vPadding = 0) => {
+export const alwaysAboveRightOf = (
+    elementRect: Pick<DOMRect, "left" | "top">,
+    chevronFace = ChevronFace.None,
+    vPadding = 0,
+) => {
     const menuOptions: IPosition & { chevronFace: ChevronFace } = { chevronFace };
 
     const buttonLeft = elementRect.left + window.pageXOffset;

src/components/views/rooms/EventTile.tsx

@@ -39,7 +39,7 @@ import { E2EState } from "./E2EIcon";
 import { toRem } from "../../../utils/units";
 import RoomAvatar from "../avatars/RoomAvatar";
 import MessageContextMenu, { IEventTileOps } from "../context_menus/MessageContextMenu";
-import { aboveLeftOf } from '../../structures/ContextMenu';
+import { aboveRightOf } from '../../structures/ContextMenu';
 import { objectHasDiff } from "../../../utils/objects";
 import Tooltip from "../elements/Tooltip";
 import EditorStateTransfer from "../../../utils/EditorStateTransfer";
@@ -230,7 +230,7 @@ interface IState {
 
     // Position of the context menu
     contextMenu?: {
-        position: Pick<DOMRect, "right" | "top" | "bottom">;
+        position: Pick<DOMRect, "top" | "left" | "bottom">;
         showPermalink?: boolean;
     };
 
@@ -972,7 +972,7 @@ export class UnwrappedEventTile extends React.Component<IProps, IState> {
         this.setState({
             contextMenu: {
                 position: {
-                    right: ev.clientX,
+                    left: ev.clientX,
                     top: ev.clientY,
                     bottom: ev.clientY,
                 },
@@ -1017,7 +1017,7 @@ export class UnwrappedEventTile extends React.Component<IProps, IState> {
 
         return (
             <MessageContextMenu
-                {...aboveLeftOf(this.state.contextMenu.position)}
+                {...aboveRightOf(this.state.contextMenu.position)}
                 mxEvent={this.props.mxEvent}
                 permalinkCreator={this.props.permalinkCreator}
                 eventTileOps={eventTileOps}