The tags display in Picard’s main window ignores tag changes made by scripts. For example, if I have a script to create the id3 TXXX frame “test” (like $copy(_id3:TXXX:test,artist), this new tag is not displayed in the list of tags.
What is more, if the option “remove existing tags” is checked and the tag is already present, it is listed as one of the tags that will be removed when the file is saved, even if the active script will make sure that the tag will be written again.
This is very confusing. A solution would be to update the list of tags every time a script is run and to show all modified tags, whether they have been modified by Picard’s core functionality, a plug-in or a script. It should also be smart enough to detect that a tag will be rewritten if existing tags are to be removed, so that it will not be marked as a tag that will be deleted when the file is saved.