Add missing "Open..." file menu

packages/notebook-extension/schema/edit-notebook-metadata.json

@@ -3,6 +3,15 @@
   "description": "Jupyter Notebook Menu Entries",
   "jupyter.lab.menus": {
     "main": [
+      {
+        "id": "jp-mainmenu-file",
+        "items": [
+          {
+            "command": "notebook:open-tree-tab",
+            "rank": 1
+          }
+        ]
+      },
       {
         "id": "jp-mainmenu-edit",
         "items": [

packages/notebook-extension/src/index.ts

@@ -177,6 +177,31 @@ const closeTab: JupyterFrontEndPlugin<void> = {
   },
 };
 
+/**
+ * Add a command to open the tree view from the notebook view
+ */
+const openTreeTab: JupyterFrontEndPlugin<void> = {
+  id: '@jupyter-notebook/notebook-extension:open-tree-tab',
+  description:
+    'Add a command to open a browser tab on the tree view when clicking "Open...".',
+  autoStart: true,
+  optional: [ITranslator],
+  activate: (app: JupyterFrontEnd, translator: ITranslator | null) => {
+    const { commands } = app;
+    translator = translator ?? nullTranslator;
+    const trans = translator.load('notebook');
+
+    const id = 'notebook:open-tree-tab';
+    commands.addCommand(id, {
+      label: trans.__('Open…'),
+      execute: async () => {
+        const url = URLExt.join(PageConfig.getBaseUrl(), 'tree');
+        window.open(url);
+      },
+    });
+  },
+};
+
 /**
  * The kernel logo plugin.
  */
@@ -570,6 +595,7 @@ const editNotebookMetadata: JupyterFrontEndPlugin<void> = {
 const plugins: JupyterFrontEndPlugin<any>[] = [
   checkpoints,
   closeTab,
+  openTreeTab,
   editNotebookMetadata,
   kernelLogo,
   kernelStatus,