Developer reply by C-E
Rated 4 out of 5 stars
I really like this program, but there is a bug. I didn't see a place to report the bug.
What happens is that occasionally when switching from one inbox to another, Start with Inbox will get stuck in a loop and keep switching back and forth between two folders. The only way to stop this is to restart Firefox.
I am using Firefox 115.4.2 (64-bit) on Windows 10.
Please contact me via k-l-p@gmx.de.
(You wrote Firefox, but you mean Thunderbird, correct?
Update 04.12.2023:
Do the problem still exist if you use version 4.2.3 of the Add-on?
To create your own collections, you must have a Mozilla Add-ons account.