No kidding, this is a serious question. In options > tags there is a subsection "remove" with checkboxes for ID3v1, ID3v2 and APE.
The helpfile only says "ID3v1 if enabled, Mp3tag removes an existing ID3v1 tag." (idem for v2 and ape). But what it fails to say (and I would add this to the help file to make it clearer) is when this kind of tag is removed.
a) only when the user clicks on "remove tag" (CTRL+R) ?
B) whenever tags are edited (because technically the existing tags are removed and the new, edited tags are then added) ?
And in this scenario, what happens if impossible combinations are selected in the options? (i.e. write ID3v1 enabled and remove ID3v1 enabled)
Of course I tried out before asking, but I got mixed results and I am somewhat confused now, PLUS I don't want to lose tags I didn't intend to discard, so I want to be sure, too, by posting this message.