select one column for the Actions
ex. to convert all songs Artist column into Mixed Case only not all [ex.] album, title
put again the Undo for Cover Image Tag changes
[if you wish to revert again to that cover image tag]
notify for the Context Menu - Remove Tag...
there's no message box for assurance
in Extended Tag Mode - save to clipboard
add an option to Option>Tags to save to clipboard
for example Extended Tag Mode...change all tags of all selected songs then have it Save All when finished...clipboard will handle all changes to all selected songs...
also add an Undo in the Extended Tag Mode