src/vs/workbench/contrib/markers/browser/markersView.ts/MarkersView/hasSelectedMarkerFor
class MarkersView:	private hasSelectedMarkerFor(resource: ResourceMarkers): boolean {
		if (this.tree) {
			let selectedElement = this.tree.getSelection();
			if (selectedElement && selectedElement.length > 0) {
				if (selectedElement[0] instanceof Marker) {
					if (resource.has((<Marker>selectedElement[0]).marker.resource)) {
						return true;
					}
				}
			}
		}
		return false;
	}