it's probably because you haven't installed Kvantum and enabled the Kvantum theme linked in the theme's description.
KDE
KDE is an international technology team creating user-friendly free and open source software for desktop and portable computing. KDE’s software runs on GNU/Linux, BSD and other operating systems, including Windows.
Plasma 6 Bugs
If you encounter a bug, proceed to https://bugs.kde.org/, check whether it has been reported.
If it hasn't, report it yourself.
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Developers do not look for reports on social media, so they will not see it and all it does is clutter up the feed.
I got it installed, not sure if it was nature of theme or if I did it correctly. It felt really off to me, luckily it was on a test user which I deleted now. Installing and configuring Kvantum felt like blindly groping in the bathroom with soap all over face.
I won't be experimenting with it anytime in near future.
Sad to hear you had that experience. Someone posted some blog posts about complete KDE themes here a while back. I had very good results following the instructions in those blog posts. Each one had icons, window, plasma, gtk, wallpaper, and whatever else was needed. I stuck with "shades of purple" for ages, which would normally not be my first choice of theme.
Is Kvantum worth using?
Kvantum allows much more complex theming, compared to what you can achieve with regular Qt themes, but whether it's worth it or not, that's for you to decide
I hear that. I used to be heavily into theming/skinning my desktop back when Windows XP hit the scene, but nowadays I just like something consistent. I guess I’ll probably test it out on one of my testing units and see if I like it.
Complexity doesn't imply inconsistency, but i hear you. Find a theme you like, and if it needs kvantum, then try it out, and if not, then don't. It's not like it's required to enjoy Plasma
Yeah no I got that. I. Ever said anything about complexity being inconsistent I merely stated it is what I appreciate most in theming.
Regular Qt themes are compiled C++ programs that use the QStyle API to alter the look of Qt applications. They can do just about anything, but obviously require code to create. Being compiled programs also means they can't be portably distributed. They have to be recompiled for every different Qt version and architecture.
Kvantum is just one of those themes, and it uses its code to load and display much simpler SVG-based themes. Kvantum themes are actually much less complex than regular Qt themes, which is the whole point, since that makes them significantly simpler to create and much more portable, which is why they're so popular. The vast majority of Qt themes nowadays are made for Kvantum. Before Kvantum, it was mostly the less powerful QtCurve. Regular themes can do a lot of things Kvantum themes can't, but Kvantum is usually good enough.
I thought Kvantum is not longer actively developed / maintained?