message: prevent badge jumping when hovering over sublist
  this was caused by the layout growing wider than it could,
  hence the overflow event being triggered.
  The overflow event is only supported in FF and we fire the
  manual check often enough that the overflow gradient still
  reliably (dis)appears when needed.
diff: @@ -102,10 +102,6 @@ export default class AutoHideScrollbar extends React.Component {
  installBodyClassesIfNeeded();
  this._needsOverflowListener =
  document.body.classList.contains("mx_scrollbar_nooverlay");
  - if (this._needsOverflowListener) {
  - this.containerRef.addEventListener("overflow", this.onOverflow);
  - this.containerRef.addEventListener("underflow", this.onUnderflow);
  - }
  this.checkOverflow();
  }
  @@ -118,13 +114,6 @@ export default class AutoHideScrollbar extends React.Component {
  }
  }
  - componentWillUnmount() {
  - if (this._needsOverflowListener && this.containerRef) {
  - this.containerRef.removeEventListener("overflow", this.onOverflow);
  - this.containerRef.removeEventListener("underflow", this.onUnderflow);
  - }
  - }
  -
  render() {
  return (<div
  ref={this._collectContainerRef}
  