If you followed my advice in the article on piloting 5.0 then you did this:
- System > Preferences or xTuple > Preferences > Application
- Change the setting of Use Native Application Styling
If you followed that advice, flip that flag back and look again.
That preference significantly changes the appearance of the application. My goal with that recommendation was to reduce confusion about which copy of the database you were working with — the 5.0 pilot or the production database. As I said there:
I strongly recommend making some simple visual change to make it look different from your production database
If you didn't change that preference then there's something else going on, likely related to our upgrading to a newer version of Qt.