Play button disappears randomly

My run button seems to disappear randomly while working in a notebook.
Actively refreshing the page in the browser (firefox) helps to get it back.
Any clue what could cause this.

normal button bar
Screenshot 2022-03-23 at 13.14.37

at random times, the play button disappears
Screenshot 2022-03-23 at 13.14.07

I’m running Jupterlab 3.3.2 behind Jupyterhub proxied via nginx.
The user homedir is nfs mounted on the jupyterhub server


Since yesterday, the video playback button disappears quite frequently. For example, if I play a video, then stop the video, the playback button disappears.

It looks like the dom is actually modified since the placeholder for the button is still there.
I can’t find any hints in the logfiles to what could be happening.
For what its worth, I can just run the cells with enter.

I don’t think this has anything to do with my question

I have the same experience. Everytime I open a plain .py file in the editor, the “Run/Play” Button disapears. I have to close both and open the NB again, then it will be displayed again.

I made a ticket in play/run button disappears when switching between tabs · Issue #12292 · jupyterlab/jupyterlab · GitHub
I think it appeared in the triage. In between I reverted to 3.2.9 that does not have the issue

I have the same experience...

I can reproduce the issue on my local jupyterlab 3.3.2 installation on macbook using Chrome 100 without any ad blockers.

I also encountered this bug in 3.3.2, and it would happen in Chrome-based browsers whenever I switched tabs from viewing a notebook to some other tab in JupyterLab.

Upgrading to 3.3.4 appears to resolve this issue. Thanks -

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