src/vs/editor/contrib/colorPicker/browser/colorPickerWidget.ts/Strip/onPointerDown
class Strip:	private onPointerDown(e: PointerEvent): void {
		if (!e.target || !(e.target instanceof Element)) {
			return;
		}
		const monitor = this._register(new GlobalPointerMoveMonitor());
		const origin = dom.getDomNodePagePosition(this.domNode);
		this.domNode.classList.add('grabbing');

		if (e.target !== this.slider) {
			this.onDidChangeTop(e.offsetY);
		}

		monitor.startMonitoring(e.target, e.pointerId, e.buttons, event => this.onDidChangeTop(event.pageY - origin.top), () => null);

		const pointerUpListener = dom.addDisposableListener(document, dom.EventType.POINTER_UP, () => {
			this._onColorFlushed.fire();
			pointerUpListener.dispose();
			monitor.stopMonitoring(true);
			this.domNode.classList.remove('grabbing');
		}, true);
	}