message: also put read marker past (like RR) invisible events
diff: @@ -747,6 +747,7 @@ const TimelinePanel = React.createClass({
  const lastDisplayedIndex = this._getLastDisplayedEventIndex({
  allowPartial: true,
  ignoreEchoes: true,
  + allowEventsWithoutTiles: true,
  });
  if (lastDisplayedIndex === null) {
  