src/vs/base/browser/ui/splitview/paneview.ts/PaneDraggable/render
class PaneDraggable:	private render(): void {
		let backgroundColor: string | null = null;

		if (this.dragOverCounter > 0) {
			backgroundColor = (this.pane.dropBackground || PaneDraggable.DefaultDragOverBackgroundColor).toString();
		}

		this.pane.dropTargetElement.style.backgroundColor = backgroundColor || '';
	}