First of all, thank you for maintaining this useful utility. I have made a modest contribution awhile ago.
Many a time when editing a list of tracks, when they are all loaded and selected, after all the manual entries for Album artist, album title, composer, publisher, etc are done and I hit add cover and click OK on it, I by mistake sometimes double click that causes it to react by selecting a track as the mouse cursor after the image selection dialogue is closed stays over the same area, i.e. over selected track. Unless I every time save the editing before I add covers, I end up losing all th e just made entries as when selecting a single track they disappear.
Have a confirmation box when the user changes track selection by clicking a single track when all tracks are selected.