cannot write in jupyter cell

Hi everyone,

I never had this issue before, but when I add a new cell between existing cells, I cannot write in it. I'm able to copy and paste from an existing cell into the new one, but I may just delete the content and I'm not able to modify it.
I tried restarting the kernel, the workstation, but it doesn't solve the problem.
It doesn't seem related to the keyboard layout (cf. issue #2379), because mine it's US.

Thanks in advance for any suggestion.
Kind regards,
-Elena

Start by reproducing the problem in Jupyter Notebook: insert a cell between existing cells and try typing, deleting pasted content, and editing after restarting the kernel and workstation. Compare the new cell with an existing editable cell and record the environment details needed to isolate the cause. Done means newly inserted cells accept keyboard edits reliably.

Written by the indexing model from the issue text.