I've already taken this up with the Foobar Forum, but, it may be a DOpus problem. I'm using Foobar2000 music player to add Replaygain to my music tracks on my PC. Replaygain, for those not in the know adds tags to the files so that when they play the album gain is adjusted so that all albums play at a similar level. This is what I am doing and the problem I've encountered:
Scan an album for Replaygain with Foobar2000, add the tags then go to DOpus, and find that tag operations with Foobar mess up the display of tags in DOpus. I highlight all the tracks in DOpus, go to Properties where I see the tags correctly, activate a field so that the Apply button activates then click Apply on the Properties page and I then find all the normal tags return including title etc. After doing this I was checking back with Foobar using the Edit Replaygain command and saw that all tags were retained, but, after doing that a dozen times I presumed everything was going OK so stopped checking that. Now, however, after adding Replaygain to all my albums I thought I was hearing a marked difference in volume between different albums so checked and found no Replaygain on any of the albums, the Replay Tags had gone.
So I'm puzzled here about what's happening. Adding Replaygain seems to destroy presentation of tags in DOpus, repairing tags in DOpus seems to (at some time) remove Replaygain tags. Other users of DOpus seem to have not reported this issue so I'm beginning to think it may be a problem with mp3 tags in DOpus. Foobar is set to write tags in ID3v2 + ID3v1 format, DOpus has mp3 tags set to "Save ID3v1 Tag as well" so I would have thought the two apps were compatible. Are there any settings I've overlooked? Or is this a problem with mp3 tags that has been overcome in more recent versions of DOpus?