src/vs/base/browser/ui/list/listView.ts/ListView/onMouseMiddleClick
class ListView:	@memoize get onMouseMiddleClick(): Event<IListMouseEvent<T>> { return Event.filter(Event.map(this.disposables.add(new DomEmitter(this.domNode, 'auxclick')).event, e => this.toMouseEvent(e as MouseEvent), this.disposables), e => e.browserEvent.button === 1, this.disposables); }