Tweak resizer collapse distributor behaviour to work with the expanding space panel

src/components/structures/LoggedInView.tsx

@@ -223,7 +223,14 @@ class LoggedInView extends React.Component<IProps, IState> {
         let size;
         let collapsed;
         const collapseConfig: ICollapseConfig = {
-            toggleSize: 260 - 50,
+            // TODO: the space panel currently does not have a fixed width,
+            // just the headers at each level have a max-width of 150px
+            // Taking 222px for the space panel for now,
+            // so this will look slightly off for now,
+            // depending on the depth of your space tree.
+            // To fix this, we'll need to turn toggleSize
+            // into a callback so it can be measured when starting the resize operation
+            toggleSize: 222 + 68,
             onCollapsed: (_collapsed) => {
                 collapsed = _collapsed;
                 if (_collapsed) {
@@ -244,6 +251,9 @@ class LoggedInView extends React.Component<IProps, IState> {
                 if (!collapsed) window.localStorage.setItem("mx_lhs_size", '' + size);
                 this.props.resizeNotifier.stopResizing();
             },
+            isItemCollapsed: domNode => {
+                return domNode.classList.contains("mx_LeftPanel_minimized");
+            },
         };
         const resizer = new Resizer(this._resizeContainer.current, CollapseDistributor, collapseConfig);
         resizer.setClassNames({

src/resizer/distributors/collapse.ts

@@ -22,6 +22,7 @@ import Sizer from "../sizer";
 export interface ICollapseConfig extends IConfig {
     toggleSize: number;
     onCollapsed?(collapsed: boolean, id: string, element: HTMLElement): void;
+    isItemCollapsed(element: HTMLElement): boolean;
 }
 
 class CollapseItem extends ResizeItem<ICollapseConfig> {
@@ -31,6 +32,11 @@ class CollapseItem extends ResizeItem<ICollapseConfig> {
             callback(collapsed, this.id, this.domNode);
         }
     }
+
+    get isCollapsed() {
+        const isItemCollapsed = this.resizer.config.isItemCollapsed;
+        return isItemCollapsed(this.domNode);
+    }
 }
 
 export default class CollapseDistributor extends FixedDistributor<ICollapseConfig, CollapseItem> {
@@ -39,11 +45,12 @@ export default class CollapseDistributor extends FixedDistributor<ICollapseConfi
     }
 
     private readonly toggleSize: number;
-    private isCollapsed = false;
+    private isCollapsed: boolean;
 
     constructor(item: CollapseItem) {
         super(item);
         this.toggleSize = item.resizer?.config?.toggleSize;
+        this.isCollapsed = item.isCollapsed;
     }
 
     public resize(newSize: number) {