I am using MP3tag 2.37a under WinXP on an NTFS partition. When I browse in a folder (CTRL-D) with a lot of subfolders (185 subfolders) the complete list of subfolders is only shown the first time that folder is chosen. After working on a particular subfolder and then hitting CTRL-D again only the currently active subfolder is shown, not the whole list of subfolders. It occurs no matter if the option "subdirectories" is checked or not. Also, this error does not occur in folders with a "small" amount of subfolders (didn't check which number of subfolders is the threshold). There are several workarounds: 1. limit the number of subfolders 2. change to a different folder, then open the folder with the large amount of subfolders again. However, it would be great to see this bug confirmed and eventually fixed.
Apart from that MP3tag is a great piece of software and the best MP3 editor under the Windows sun for me :-)
Edit: I just experimented a bit more. It seems that when choosing a folder with lots of subfolders for the second time it is just not expanded properly. Clicking on the "+" sign in front of the folder expands it again. Maybe someone else can confirm this because it can well be OS behavior instead of MP3Tag. If it is MP3tag's function though I would like to see it keeping the folder expanded.