Starting a Wine Application with a specific GTK Theme

[nate-eastman]

I know what you're thinking: we all know how to make an application (like Scrivener) use a specific GTK theme on launch by starting it with:

GTK_THEME=Adwaita:light Scrivener %F

But how do you do this for an application running in WINE? Obviously, windows themes aren't sensible to GTK variables, but in this case I have a windows application, configured to run in dark mode, that gets a light-mode window decoration. It kills the mood.
Here's what I've figured out doesn't work:

1. Running the full command like so:

   GTK_THEME=Adwaita:light Playonlinux "Scrivener" %F

2. Launching

   env GTK_THEME=Adwaita:light Playonlinux "Scrivener" %F

   from the exec line of a .desktop file.
3. Creating a shell script that launches the WINE application (so that the terminal command is GTK_THEME=Adwaita:light Scrivener) and the "Scrivener" executable is a shell script that's just

   Playonlinux "Scriverner" %F

In all these cases, Scrivener launches successfully with whichever theme GNOME is using, and not with the theme specified by GTK_THEME. I can get Scrivener to run with a dark titlebar if I switch my entire desktop to Adwaita-dark. Other applications, like Firefox, launch using whichever theme I specify with GTK_THEME, so my working theory is that something in the way the Playonlinux scripts that launch Scrivener are configured keeps GTK_THEME from being passed all the way down to whatever the executable is.