src/vs/editor/contrib/colorPicker/colorPickerWidget.ts/Strip/constructor
class Strip:	constructor(container: HTMLElement, protected model: ColorPickerModel) {
		super();
		this.domNode = dom.append(container, $('.strip'));
		this.overlay = dom.append(this.domNode, $('.overlay'));
		this.slider = dom.append(this.domNode, $('.slider'));
		this.slider.style.top = `0px`;

		this._register(dom.addDisposableGenericMouseDownListner(this.domNode, e => this.onMouseDown(e)));
		this.layout();
	}