Impossible to save "Show list left" division width

Hi,
I have a problem saving the screen layout. This occurs with at least both versions 11.3.2 and 11.4.1.
If I choose horizontal division (Show top list) and set the width of the list, it is saved and stays that way.
If I use vertical division (Show list left), the division width of the list and detail is not saved. When the modul is called up again or even when the list is reloaded with the reload button, the division between list and detail always returns to the default (very narrow) division. It occurs on Firefox and Chrome.
Have I missed something here or is it a bug?
Thank you and best regards,
Hans

No, I can't see any errors in the logs or browser console. I will continue searching and updating here if I can solve the problem.
Greetings Hans