Fix WidgetStore wrongly hanging onto old Widget definitions during removal

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/stores/WidgetEchoStore.js

@@ -55,7 +55,7 @@ class WidgetEchoStore extends EventEmitter {
             const widgetId = w.getStateKey();
             // If there's no echo, or the echo still has a widget present, show the *old* widget
             // we don't include widgets that have changed for the same reason we don't include new ones,
-            // ie. we'd need to fake matrix events to do so and therte's currently no need.
+            // ie. we'd need to fake matrix events to do so and there's currently no need.
             if (!roomEchoState[widgetId] || Object.keys(roomEchoState[widgetId]).length !== 0) {
                 echoedWidgets.push(w);
             }

src/stores/WidgetStore.ts

@@ -122,6 +122,15 @@ export default class WidgetStore extends AsyncStoreWithClient<IState> {
         if (!room) return;
         const roomInfo = this.roomMap.get(room.roomId);
         roomInfo.widgets = [];
+
+        // first clean out old widgets from the map which originate from this room
+        // otherwise we are out of sync with the rest of the app with stale widget events during removal
+        Array.from(this.widgetMap.values()).forEach(app => {
+            if (app.roomId === room.roomId) {
+                this.widgetMap.delete(app.id);
+            }
+        });
+
         this.generateApps(room).forEach(app => {
             this.widgetMap.set(app.id, app);
             roomInfo.widgets.push(app);