src/vs/workbench/contrib/markers/browser/markersView.ts/MarkersView/setTreeSelection
class MarkersView:	private setTreeSelection(): void {
		if (this.tree && this.tree.isVisible() && this.tree.getSelection().length === 0) {
			const firstVisibleElement = this.tree.firstVisibleElement;
			const marker = firstVisibleElement ?
				firstVisibleElement instanceof ResourceMarkers ? firstVisibleElement.markers[0] :
					firstVisibleElement instanceof Marker ? firstVisibleElement : undefined
				: undefined;
			if (marker) {
				this.tree.setFocus([marker]);
				this.tree.setSelection([marker]);
			}
		}
	}