message: Fix left spaces not disappearing from the space panel
diff: @@ -196,14 +196,17 @@ export class SpaceStoreClass extends AsyncStoreWithClient<IState> {
  };
  public rebuild = throttle(() => { // exported for tests
  - const visibleRooms = this.matrixClient.getVisibleRooms();
  -
  - // Sort spaces by room ID to force the loop breaking to be deterministic
  - const spaces = sortBy(this.getSpaces(), space => space.roomId);
  - const unseenChildren = new Set<Room>([...visibleRooms, ...spaces]);
  + // get all most-upgraded rooms & spaces except spaces which have been left (historical)
  + const visibleRooms = this.matrixClient.getVisibleRooms().filter(r => {
  + return !r.isSpaceRoom() || r.getMyMembership() === "join";
  + });
  + const unseenChildren = new Set<Room>(visibleRooms);
  const backrefs = new EnhancedMap<string, Set<string>>();
  + // Sort spaces by room ID to force the loop breaking to be deterministic
  + const spaces = sortBy(visibleRooms.filter(r => r.isSpaceRoom()), space => space.roomId);
  +
  // TODO handle cleaning up links when a Space is removed
  spaces.forEach(space => {
  const children = this.getChildren(space.roomId);
  