src/vs/workbench/browser/contextkeys.ts/WorkbenchContextKeysHandler/updateInputContextKeys
class WorkbenchContextKeysHandler:	private updateInputContextKeys(): void {

		function activeElementIsInput(): boolean {
			return !!document.activeElement && (document.activeElement.tagName === 'INPUT' || document.activeElement.tagName === 'TEXTAREA');
		}

		const isInputFocused = activeElementIsInput();
		this.inputFocusedContext.set(isInputFocused);

		if (isInputFocused) {
			const tracker = trackFocus(document.activeElement as HTMLElement);
			Event.once(tracker.onDidBlur)(() => {
				this.inputFocusedContext.set(activeElementIsInput());

				tracker.dispose();
			});
		}
	}