message: Null-guard for missing root event in thread panel
diff: @@ -81,7 +81,7 @@ const useFilteredThreadsTimelinePanel = ({
  // The proper list order should be top-to-bottom, like in social-media newsfeeds.
  filteredThreads.reverse().forEach(([id, thread]) => {
  const event = thread.rootEvent;
  - if (timelineSet.findEventById(event.getId()) || event.status !== null) return;
  + if (!event || timelineSet.findEventById(event.getId()) || event.status !== null) return;
  timelineSet.addEventToTimeline(
  event,
  timelineSet.getLiveTimeline(),
  