Ubuntu – Illogical GTK theme behaviour on Ubuntu 18.04

gnomegtkthemes

I'm using X-Arc-White GTK theme in my freshly installed Ubuntu 18.04 desktop. I looks really amazing, but there's a problem with GNOME own applications, like system monitor or calculator. They are shown only with default Adwaita theme.

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The only themes which work for all programs are Ambiance and Radiance. Is there a reason for that behaviour?

Best Answer

It seems those are applications installed as snap packages. You may verify it by running 

snap list

The snap execution environment doesn't see any of the themes on your system (local or system-wide). So this is somewhat an expected behaviour.

As a workaround you may remove those snap applications by running 

snap remove <package-name>

and install their apt versions by running 

sudo apt install <package-name>
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