Custom GTK3 Theme for Flatpak

The Interim Fix for Flatpak Theming

If you are familiar with Flatpak, you will know that unless there’s already a Flatpak package for the theme you are using, it will use the default GTK3 theme which makes your app stick out like a soar thumb. Unfortunately, Flatpak is at the same time is quickly becoming the choice of distribution method for many of my favorite applications like Geary. So I end up having to spin up my own ppa just so I can continue to update via apt.

Well thanks to this post, and especially for those of you who are not inclined to or don’t know how to maintain your own PPA, here’s an interim fix to have your Flatpak apps using the same theme as the custom one you are using in Gnome. The down side is that you will have to do this again for apps that use a different RunTime folder than the ones you have fixed. You may also have to do this again on each Flatpak update?

For the purpose of this example, I will be using a Flatpak app called Rest Scope.

Don’t let the screenshot in flathub fool you. The dark theme is not the default. After installing this app, you will notice that the app launches with a default…