src/vs/workbench/contrib/markers/browser/markersView.ts/MarkersView/collapseAll
class MarkersView:	collapseAll(): void {
		if (this.tree) {
			this.tree.collapseAll();
			this.tree.setSelection([]);
			this.tree.setFocus([]);
			this.tree.getHTMLElement().focus();
			this.tree.focusFirst();
		}
	}