Thunderbird 115.7.0 (64-bit) threading bug
When I move an email from my Inbox to a folder, every now and again the screen refreshes and I find the emails in my Inbox are now threaded. I turn off threading by View>Sort By>Unthreaded and the view reverts to how I want it . . . until I move another message to a folder when (sometimes) the same thing happens again. Please advise, as it gets extremely annoying to have to repeatedly turn off the Threaded view.
Alla svar (1)
This may not resolve your longterm issue, but will change the default from threaded to unthreaded:
To change default for *new* folders, In config editor, you can change default that applies to NEW folders you set up: mailnews.default_view_flags 0=unthreaded
Config editor is available at Tools>settings>general and scroll to bottom right.