[AccessD] Why would one title bar be a different color?

I'm pulling my hair on this one.  In another database, I built a form that
picked up a dark gray title bar.  I'm using a dark gray Office Theme, so I
wasn't too surprised.  I imported that form into another database using the
dark gray Office theme where the forms have white title bars.  The imported
form shows a dark gray title bar.  Both of the database had the Use
Windows-Themed controls turned on when the forms were created.  I didn't
turn it off until I tried to troubleshoot the difference, and it didn't
have any effect one way or the other.  All new forms I create in the
existing database come up with white title bars.  Has anyone ever see this
in Access 2010 or 2013?

I will rebuild the form (I will anyhow, it's just a menu), but I'm
concerned because I have to insulate this app against surprises once I hand
it over.  If something will cause a persistent design difference between
forms, I need to prepare for that.

Charlotte