make that there is always a focus element in the peek tree, #89557

src/vs/workbench/contrib/callHierarchy/browser/callHierarchyPeek.ts

@@ -383,7 +383,7 @@ export class CallHierarchyTreePeekWidget extends peekView.PeekViewWidget {
 
 		} else {
 			this._parent.dataset['state'] = State.Data;
-			if (!viewState) {
+			if (!viewState || this._tree.getFocus().length === 0) {
 				this._tree.setFocus([root.children[0].element]);
 			}
 			this._tree.domFocus();