Create a new notebook with a specific kernel from the new dropdown

packages/docmanager-extension/src/index.ts

@@ -40,7 +40,10 @@ const opener: JupyterFrontEndPlugin<IDocumentWidgetOpener> = {
     const pathOpener = notebookPathOpener ?? defaultNotebookPathOpener;
     let id = 0;
     return new (class {
-      open(widget: IDocumentWidget, options?: DocumentRegistry.IOpenOptions) {
+      async open(
+        widget: IDocumentWidget,
+        options?: DocumentRegistry.IOpenOptions
+      ) {
         const widgetName = options?.type ?? '';
         const ref = options?.ref;
         // check if there is an setting override and if it would add the widget in the main area
@@ -54,6 +57,9 @@ const opener: JupyterFrontEndPlugin<IDocumentWidgetOpener> = {
             (widgetName === 'default' && ext === '.ipynb') ||
             widgetName.includes('Notebook')
           ) {
+            // make sure to save the notebook before opening it in a new tab
+            // so the kernel info is saved
+            await widget.context.save();
             route = 'notebooks';
           }
           // append ?factory only if it's not the default

packages/tree-extension/src/index.ts

@@ -87,7 +87,7 @@ const createNew: JupyterFrontEndPlugin<void> = {
     translator: ITranslator,
     toolbarRegistry: IToolbarWidgetRegistry | null
   ) => {
-    const { commands } = app;
+    const { commands, serviceManager } = app;
     const trans = translator.load('notebook');
 
     const overflowOptions = {
@@ -99,18 +99,35 @@ const createNew: JupyterFrontEndPlugin<void> = {
     newMenu.title.icon = caretDownIcon;
     menubar.addMenu(newMenu);
 
-    const newCommands = [
-      'notebook:create-new',
-      'terminal:create-new',
-      'console:create',
-      'filebrowser:create-new-file',
-      'filebrowser:create-new-directory',
-    ];
+    const populateNewMenu = () => {
+      // create an entry per kernel spec for creating a new notebook
+      const specs = serviceManager.kernelspecs?.specs?.kernelspecs;
+      for (const name in specs) {
+        newMenu.addItem({
+          args: { kernelName: name, isLauncher: true },
+          command: 'notebook:create-new',
+        });
+      }
+
+      const baseCommands = [
+        'terminal:create-new',
+        'console:create',
+        'filebrowser:create-new-file',
+        'filebrowser:create-new-directory',
+      ];
 
-    newCommands.forEach((command) => {
-      newMenu.addItem({ command });
+      baseCommands.forEach((command) => {
+        newMenu.addItem({ command });
+      });
+    };
+
+    serviceManager.kernelspecs?.specsChanged.connect(() => {
+      newMenu.clearItems();
+      populateNewMenu();
     });
 
+    populateNewMenu();
+
     if (toolbarRegistry) {
       toolbarRegistry.addFactory(
         FILE_BROWSER_FACTORY,

ui-tests/test/smoke.spec.ts

@@ -27,7 +27,7 @@ test.describe('Smoke', () => {
     const [notebook] = await Promise.all([
       page.waitForEvent('popup'),
       page.click('text="New"'),
-      page.click('text="Notebook"'),
+      page.click('text="Python 3 (ipykernel)"'),
     ]);
 
     try {