src/vs/workbench/browser/parts/editor/tabsTitleControl.ts/TabsTitleControl/originatesFromTabActionBar
class TabsTitleControl:	private originatesFromTabActionBar(e: MouseEvent | GestureEvent): boolean {
		let element: HTMLElement;
		if (e instanceof MouseEvent) {
			element = (e.target || e.srcElement) as HTMLElement;
		} else {
			element = (e as GestureEvent).initialTarget as HTMLElement;
		}

		return !!findParentWithClass(element, 'action-item', 'tab');
	}