for the next v3.1 update, MB will refresh the main panel with the removed cuesheet if you delete an external cuesheet and right click/ Send To/ File Rescan
or you edit the cuesheet in the tag editor and blank it out
Thanks! I just checked the changes but I think it could improve further to be really useful.
(1) embedded cuesheets
As you said, now clearing cuesheet content via tag editor immediately removes the duplicates from the main panel. But the problem is "Edit cuesheet" button shouldn't show up in tag editor in the first place if the file no longer contains embedded cuesheet, but it still does and the user has to clear up no-longer-existing cuesheets from each file (and those files can be a lot depending on the track count). What I'm suggesting is if the user removes cuesheet tag from files first, the main panel should immediately (or with file rescan) refresh and remove all duplicate files from those removed cuesheets. And tag editor shouldn't show "Edit Cuesheet" button for those files because they don't contain cuesheets any more.
(2) external cuesheets
I can see now removing an external cue file and file rescanning for the file immediately removes cuesheet-generated files from the main panel. But if I re-add the cue file to the same folder and run file rescan, MB doesn't recognize it. What's required additionally is folder rescan. But if it can detect a disappearance of a cue file from the same folder with a simple file rescan, shouldn't it be able to detect an addition of the cue file (with the same name as the music file) as well?