properly dispose tree items

related to #46565

src/vs/base/parts/tree/browser/treeView.ts

@@ -1675,6 +1675,11 @@ export class TreeView extends HeightMap {
 		}
 		this.domNode = null;
 
+		if (this.items) {
+			Object.keys(this.items).forEach(key => this.items[key].removeFromDOM());
+			this.items = null;
+		}
+
 		if (this.context.cache) {
 			this.context.cache.dispose();
 			this.context.cache = null;

src/vs/workbench/parts/files/electron-browser/views/explorerViewer.ts

@@ -226,6 +226,7 @@ export class FileRenderer implements IRenderer {
 	}
 
 	public disposeTemplate(tree: ITree, templateId: string, templateData: IFileTemplateData): void {
+		templateData.elementDisposable.dispose();
 		templateData.label.dispose();
 	}