Ultra wide window margin in some windows

Hi, I'm using Zorin OS Lite 15.1. Everything is running fine, but a few days ago some windows begin to show a wide gray margin. It happens in some already installed apps like the Software App, Zorin Appearence, Text Editor, Calculator, Firefox, etc. but not in other apps like Terminal, File Manager, LibreOffice or Task Manager. Every app I installed after the OS installation is working right, without those weird frames around the app window.

I tried to switch off the Window Compositor in the Windows Manager Settings, but doesn't solve the problem.

Any idea about how to solve it? Thank you.

2 screenshots of the issue in light and dark theme:

luis wrote:Hi, I'm using Zorin OS Lite 15.1. Everything is running fine, but a few days ago some windows begin to show a wide gray margin. It happens in some already installed apps like the Software App, Zorin Appearence, Text Editor, Calculator, Firefox, etc. but not in other apps like Terminal, File Manager, LibreOffice or Task Manager. Every app I installed after the OS installation is working right, without those weird frames around the app window.

I tried to switch off the Window Compositor in the Windows Manager Settings, but doesn't solve the problem.

Any idea about how to solve it? Thank you.

The apps you name are all GTK shell using apps, whereas the rest are the apps run using XFWM4 window manager in Zorin Lite which is XFCE4 Desktop Environment.
The reason they are so wide is because Gnome changed the layout of the window borders in gnome to be integrated- titlebar, headerbar, toolbar all in one.
Drives me nuts, too.
There is no real solution, because it is just two different designs at work. The best you can do is to use as near a matching gtk/xfwm theme you can find.

Thank you Aravisian, I've solved the issue changing the style from ZorinBlue-Dark to Adwaita Dark in the Appearance settings window.

Happy new year!

And to you, as well.