src/vs/platform/windows/node/windowTracker.ts/ActiveWindowManager/setActiveWindow
class ActiveWindowManager:	private setActiveWindow(windowId: number | undefined) {
		if (this.firstActiveWindowIdPromise) {
			this.firstActiveWindowIdPromise.cancel();
			this.firstActiveWindowIdPromise = undefined;
		}

		this.activeWindowId = windowId;
	}