Ken, in the last several betas, and apparently in the new release candidate as well, there is an issue with how thumbnails are displayed in the list if you have created a manual master profile for several boxsets.

For example:  I created a manual box called 'Battlestar' to hold all of the Battlestar Galactica box sets.  Works great, except that the last boxset added to the master breaks out the list of child discs and displays them in the thumbnail list even though the little + sign in the corner still says +.  Clicking on it to change it to a - has no effect at all.  I can shrink everything down under the master (the manually created box) with no problem, but if I try to expand the master to show the various box sets within (and not displaying the child profiles) if still breaks out the child profiles for the last box set in the master list.

Note that this only occurs in the thumbnail mode.  If I change to text mode, everything expands and contracts as it should.  I haven't used text mode since you introduced thumbnails, so I would like to see this fixed.