The problem arose after installing the system update.
In the image you can see how the window is not generated completely
The problem arose after installing the system update.
interesting!
What version of UB are you using? 22.04 ?
What theme are you using? Look in budgie desktop settings to see what is set.
if you resize the window the problem is fixed
I suspect that this will be fixed by an upcoming release of libmutter currently undergoing testing.
You can help testing by following the instructions in that bug report - the package from proposed is called libmutter-12-0
I suspect it may be a theme issue, change the theme to see if the issue continues.