Can't create a notebook file after closing a notebook file using new experimental Positron notebooks

[jonvanausdeln]

System details:

Positron and OS details:

Positron Version: 2025.04.0 (system setup) build 64
Code - OSS Version: 1.96.0
Commit: b25e187
Date: 2025-03-10T02:46:12.724Z
Electron: 32.2.6
Chromium: 128.0.6613.186
Node.js: 20.18.1
V8: 12.8.374.38-electron.0
OS: Windows_NT x64 10.0.26100

Interpreter details:

Any

Describe the issue:

This only happens with new Notebooks 2.0, not with the existing notebooks

After creating and then closing a notebook, you can't create a new one. It doesn't matter if you save the notebook or not. It doesn't seem to happen if you open an existing notebook, then create a new one.

Steps to reproduce the issue:

1. Enable the new notebook experience
2. Create a new notebook
3. Close newly created notebook
4. Try to create a new notebook

20250310-1853-03.7474945.mp4

Expected or desired behavior:

New notebook created

Were there any error messages in the UI, Output panel, or Developer Tools console?

From dev console

  ERR NO notebook document for 'untitled:Untitled-1.ipynb?jupyter-notebook': Error: NO notebook document for 'untitled:Untitled-1.ipynb?jupyter-notebook'
	at _$2Lc.getNotebookDocument (file:///c:/Program%20Files/Positron/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:72959:13)
	at $9Lc.$acceptDirtyStateChanged (file:///c:/Program%20Files/Positron/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:73472:30)
	at _$2Ac.S (file:///c:/Program%20Files/Positron/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:15585:19)
	at _$2Ac.Q (file:///c:/Program%20Files/Positron/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:15571:35)
	at _$2Ac.M (file:///c:/Program%20Files/Positron/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:15514:22)
	at _$2Ac.L (file:///c:/Program%20Files/Positron/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:15443:14)
	at UniqueContainer.value (file:///c:/Program%20Files/Positron/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:15312:43)
	at $ze.B (file:///c:/Program%20Files/Positron/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:3278:16)
	at $ze.fire (file:///c:/Program%20Files/Positron/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:3303:12)
	at $tu.fire (file:///c:/Program%20Files/Positron/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:10069:16)
	at UniqueContainer.value (file:///c:/Program%20Files/Positron/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:88235:18)
	at $ze.B (file:///c:/Program%20Files/Positron/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:3278:16)
	at $ze.fire (file:///c:/Program%20Files/Positron/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:3303:12)
	at $tu.fire (file:///c:/Program%20Files/Positron/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:10069:16)
	at MessagePortMain.<anonymous> (file:///c:/Program%20Files/Positron/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:88140:45)
	at MessagePortMain.emit (node:events:518:28)
	at MessagePortMain._internalPort.emit (node:electron/js2c/utility_init:2:2949)
workbench.desktop.main.js:18310   ERR NO notebook document for 'untitled:Untitled-1.ipynb?jupyter-notebook': Error: NO notebook document for 'untitled:Untitled-1.ipynb?jupyter-notebook'
	at $OW2.h (file:///c:/Program%20Files/Positron/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:44195:13)

[softwarenerd]

I am able to reproduce this on macOS:

And on Windows 11:

[juliasilge]

Related to #3492