src/vs/editor/contrib/suggest/browser/suggestWidget.ts/SuggestWidget/_onListMouseDownOrTap
class SuggestWidget:	private _onListMouseDownOrTap(e: IListMouseEvent<CompletionItem> | IListGestureEvent<CompletionItem>): void {
		if (typeof e.element === 'undefined' || typeof e.index === 'undefined') {
			return;
		}

		// prevent stealing browser focus from the editor
		e.browserEvent.preventDefault();
		e.browserEvent.stopPropagation();

		this._select(e.element, e.index);
	}