Hello! I have an issue in Kubuntu where the transparency does work on titlebars and borders, as well as the task manager and app-menu, however, the windows themselves remain opaque. Ofcourse firefox and the like remain opaque, but so does every program, including those that came with Kubuntu.

I wasn't too sure where to post this, if it would fit in Plasma 5, KWin, or here in Appearance and System Customization, but I feel like this is the closest one. I'm usually quite reserved when it comes to posting questions, but as I couldn't find anything about this issue anywhere, I finally decided to ask some of you fine people.

I'm running on a laptop with an AMD Ryzen 3700U with a Vega 10 graphics, maybe it could be a device specific issue? I used to run Kubuntu 20.04 with Plasma 5.18, but now I tried upgrading to 20.10 to see if the issue is still there, and it is. So the current setup is Plasma 5.19.5 and Qt 5.14.2.

The image below show's the issue to the best of my ability. As you can see, taskmanager and borders/titlebar works great, but not the contents of the window itself, and this is true for all windows.

https://i.ibb.co/YWWtbKr/screenexample.png

I've tried:

Fiddling with every setting I could get my grubby hands on

Tried at least 5 different themes

Reinstalling Kubuntu 20.04

Installing Kubuntu 20.10 (groovy gorilla)

A couple funky addons

Googled and searched a lot

Updating GPU drivers

Rebooting

I don't think I have the energy to keep fiddling with this to no avail as it seems that I'm not able to figure this out on my own... I suppose I could 'try' another distro, like Neon and see if the issue prevails? But then again, I'd like to stick with Kubuntu.

If you need anymore information, just ask and I'll reply as fast as I can.

This issue annoys me because I love fancy transparent effects, and the aesthetic of KDE was the main reason I switched to Kubuntu over Ubuntu, so if anyone of you could help me out, I (and maybe some other people down the line) would be really thankful!

PS: I have used Ubuntu for a year or so, but I'm still pretty much a newcomer as I don't have a lot of experience, so take that into account when writing (thanks!)

Transparency within the window needs to be requested by the application. Use Kvantum themes, which can override this request, and force some applications to use transparency that they didn't request.