If it helps at all, I also lost this setting (had to reset to filter bar) but I lost it when upgrading from 12.6 to 12.7 (haven't upgraded to 12.8 yet).
Many thanks for sending the config to us. We've fixed that so it won't happen again. If you chose Filter Bar now it will stick for future versions.
(As a side-effect of fixing this, anyone choosing WSL Command as the default mode in 12.8 will need to chose it again in 12.8.1/12.9. But anyone choosing that as the default is unlikely. Note that you can't currently see the WSL Command option unless Windows Subsystem for Linux is installed, which is why you were getting a blank value in the drop-down.)
Was it definitely 12.6 to 12.7, and not to 12.7.1 or another beta later than 12.7?
As far as I can tell, 12.7.1 was the first version where it might have happened. If that's not true, please let me know, as I may have missed a situation and I'd like to make sure the fix covers everything.
You're probably right, maybe it wasn't 12.6. I did have problems with 12.7.2 and I went back to 12.7 so maybe that was the time it happened. Sorry, I just don't remember to well anymore.
Just FYI, the point of the public beta program is so problems like this can be found and fixed before the general release, not after. Please report problems you find when you find them - don’t just rollback and wait for the next version.