I have some problem with 148 version Thunderbird ESR. After update from 10x.x version where MoreLayouts was installed, it stay in disabled stage. I delete extension manually from addons page, but some program leftovers stayed in THunderbird profile. The attachment panel can be expanded by pulling the separator. By default this should not be the case if you reinstall the client. I found only one file userChrome.css and delete it, but the separator also moves to any distance, including when there are a lot of attachments, a small slider appears to scroll the attachment panel (and the attachment panel area should be fixed even if there are a lot of them) This creates a problem for users. Where can I find extension remnants and remove them manually?
In the profile, you can close Tb, rename xulstore.json, restart. You can also edit xulstore.json carefully and remove references to the additional layouts. Also pref mail.pane_config.dynamic can be set to 0 (classic view), although Tb should handle invalid values.
149.0.1 (64-разрядный) its not working by default in fresh profile! specifically: the attachment bar does not stretch upward - that’s what I’m trying to achieve, that is, it is fixed and you can only pull it down.