Fix sidebar search to force-include virtual nodes (#14)

src/app/app.component.ts

@@ -93,10 +93,18 @@ export class AppComponent implements OnInit {
   }
 
   onFilterChange($event) {
-    const value = $event.detail.value.toLowerCase();
+    const query = $event.detail.value.toLowerCase();
-    this.menuTree.treeModel.filterNodes(node => {
+    this.menuTree.treeModel.clearFilter();
-      return node.data.name.toLowerCase().includes(value);
+    if ( query ) {
-    });
+      this.menuTree.treeModel.filterNodes(node => {
+        if ( node.data.virtual ) {
+          // "Virtual" tree nodes should always be shown
+          return true;
+        }
+
+        return node.data.name.toLowerCase().indexOf(query) >= 0;
+      });
+    }
   }
 
   async onNodeMenuClick($event) {