I recently tried to force the windows classic theme via GPO to ensure a standard theme for all users. However, there were some issues with an application when we used the classic theme.
Before I was able to do that, I needed to enable the Themes service which I also did via GPO. We have this service disabled by default on our image.
When you disable this service, you get a theme which looks a lot like the classic one but there are apparently some minor differences.
I then stopped and disabled the service again and set the GPO, 'Force Windows Classic Theme' back to 'Not Configured'.
Ever since then the problematic application looks like this:
But it used to look like this:
As you can see, the buttons were not flat before applying the classic theme. I also copied a theme from an other machine where the buttons are not flat and tried to apply it onto my machine but it doesn't change.
Any ideas how I can change it back to the theme without flat buttons?