Thanks for testing, so the problem isn't inside Ribbon but a whole Qt app and for this we found a solution ;-)
Can you please try to update file OrmDesigner2.plist located inside the ORMDesigner2 bundle and add following two lines?
<key>NSPrincipalClass</key>
<string>NSApplication</string>
to the beginning of element?

After that it might be needed to logout and login because of .plist files caching.
Alternatively you can download updated .plist file here. If this solution will work, it will be included in the next release.
Solution is taken from here and suggested by QtTitanRibbon creator here.