I wanted to say that the quick edit seems to be working now, but I think I jumped the gun. The "save changes" button is pressed. The message seems to be updating. But the changes are not being applied.
To be more precise, I did this: I went into advanced mode, added some text with a quote to the message, saved the changes -> the changes are not visible in the message text.
I went into quick edit mode, opened the message -> I see the changed text inside the edit window.
I press "save" -> nothing happens again.
See the previous message, plus screenshots from this one.
Configuration: updated Firefox, Win10, 1920x1080
The same situation with saving the edited message. The configuration is the same.
I still haven't been able to reproduce the problem, I guess I didn't understand the essence correctly. It would be good if one of you could record a video of all the actions leading to the problem.