src/vs/editor/contrib/zoneWidget/browser/zoneWidget.ts/ZoneWidget/_applyStyles
class ZoneWidget:	protected _applyStyles(): void {
		if (this.container && this.options.frameColor) {
			const frameColor = this.options.frameColor.toString();
			this.container.style.borderTopColor = frameColor;
			this.container.style.borderBottomColor = frameColor;
		}
		if (this._arrow && this.options.arrowColor) {
			const arrowColor = this.options.arrowColor.toString();
			this._arrow.color = arrowColor;
		}
	}