GTK apps are illegible

[loonix]

I am using KDE on some PCs and also different kinds of ARM-based SBCs. On just two of the machines (both ARM-based, but not on a third ARM - based SBC) apps such as the Synaptic Package Manager, gedit, and Firefox have fonts rendered in such a way that they are unreadable. Other apps (non-GTK) look fine. I have GTK on other Kubuntu machines, and FIrefox and gedit, at least, look just fine on those machines. What can I do to fix the broken ones? I NEED Firefox, and a few other of the affected apps on every machine.

UPDATE - I just noticed that the three machines with working GTK apps, there's something in common: In System Settings | Application Appearance- there's NO GTK icon along with the Style, Colors, Icons, Fonts, and Emoticons icons. In other words- the broken machines have a GTK icon in the list along with the other 5 named above.

[SteveRiley]

Ensure that you have the packages kde-config-gtk-style, gtk3-engines-oxygen, and gtk2-engines-oxygen installed.

Edit: misread the OP. See next post.

[SteveRiley]

Wait. I just re-read what you wrote and realized that you said that GTK+ applications work on the machines without the configuration module and the theme packages, and that the machines containing these packages are causing GTK+ applications to render poorly. I don't have an explanation for what you're seeing. Here, I have the packages and the few GTK+ applications installed work just fine. Here's how I've configured the module:

[loonix]

Many thanks for your posts, Steve. I used dpkg to list all of the installed packages. It looks like I am actually missing some packages on the machines that don't work, though they have the config package, and the working ones don't. I have yet to do a diff of the lists between working and non-working machines, that's going to happen today. Hopefully I will have this fixed. When I do, I will post what I found. I have seen a few posts around the web on the problem, but so far nobody has posted any solutions.