Delete Account button doesn't work.
After swapping to The Bat some years ago I decided to come back to Thunderbird again. So I installed Thunderbird 155.0.1 (64-bit) on my Windows 11 PC, and gradually re-created and connected the the accounts I had on the back. I also installed the ImportExportTools NG addon, then exported my emails from The Bat to Thunderbird. So far so good. However for some reason I created an account twice. There are both for the same GMX account, but one is POP and the other is iMAP. This mistake probably happened after a long session of setting things up and I just forgot about the first account.
I looked through the Thunderbird help and the answer most given was to the Thunderbird menu, select Account Settings, swap to the account you want to delete, and then press the large red DELETE BUTTON on the top level of its settings (next to the DEFAULT button). I've tried this and it doesn't work. There's no confirmation dialog (which is what I was expecting) and if I close and reboot Thunderbird the account is still there.
How can this be fixed?