message: Reset scroll offset of scrollable toolbar when item count changes.
diff: @@ -53,6 +53,13 @@ export default class Scrollable extends React.Component<ScrollableProps, Scrolla
  return true;
  }
  + public componentDidUpdate(prevProps: Readonly<ScrollableProps>): void {
  + const prevCount = Toolbar.getItemCount(prevProps);
  + const count = Toolbar.getItemCount(this.props);
  + if (prevCount !== count)
  + this.setState(() => ({ scrollOffset: 0 }));
  + }
  +
  private getVisibleItemCount() {
  if (!Scrollable.isWithDefaultProps(this.props))
  throw new TypeError();
  