src/vs/platform/windows/electron-main/windowsMainService.ts/WindowsMainService/onWindowClosed
class WindowsMainService:	private onWindowClosed(window: ICodeWindow): void {

		// Remove from our list so that Electron can clean it up
		const index = WindowsMainService.WINDOWS.indexOf(window);
		WindowsMainService.WINDOWS.splice(index, 1);

		// Emit
		this._onDidChangeWindowsCount.fire({ oldCount: this.getWindowCount() + 1, newCount: this.getWindowCount() });
	}