message: Fix 'Failed to load timeline position' regression
  Ignore the update that comes in from the RoomViewStore when the
  current room changes or we save our scoll state against the new
  room rather than the old one.
  Fixes
diff: @@ -157,6 +157,19 @@ module.exports = React.createClass({
  if (this.unmounted) {
  return;
  }
  +
  + if (!initial && this.state.roomId !== RoomViewStore.getRoomId()) {
  + // RoomView explicitly does not support changing what room
  + // is being viewed: instead it should just be re-mounted when
  + // switching rooms. Therefore, if the room ID changes, we
  + // ignore this. We either need to do this or add code to handle
  + // saving the scroll position (otherwise we end up saving the
  + // scroll position against the wrong room). Given that doing the
  + // setState here would cause a bunch of unnecessary work, we
  + // just ignore the change.
  + return;
  + }
  +
  const newState = {
  roomId: RoomViewStore.getRoomId(),
  roomAlias: RoomViewStore.getRoomAlias(),
  