That would have been a nice feature, but as far as I know, it doesn't exist.
The only way I know of finding all the tags in a graphic screen is the hard way, manually looking at every part. Even then some can be missed, because in many cases, parts get accidently copied on top of duplicate parts, so that there are 4 or 5 versions of the same part in the graphic. The only way you can "uncover" the copies is to first do a save, then do a select-and-delete of the top layer, until none are left. Only then do you know how many copies were layered.