This is my first time posting on these forums. I hope I'm not breaking any rules; I apologize if I do. I'm pretty new to Linux, having tried Ubuntu for a few months and then switching to Mint. I love my Mint KDE, but I'm having a problem as of today that I never had before.
This is true for all of the window decorations that I install in the system settings window, but not for those that were already installed - they work fine. The window decorations that I install all have the same problem: when I mouse over a button, the button disappears, and instead a small piece of my desktop OR a piece of the original Oxygen window decoration shows up instead. The button still works, but it looks really dumb, and it's becoming annoying. For now, I have switched back to the original Oxygen theme, but I really liked my airglass-black theme and want to switch back to it. I also tried glowglass-black-lite, vistairglass, and air-oxygen, and they all had the same problem.
I have already tried restarting my computer, and logging in and out of my session multiple times, but to no avail. It's persistent. Like I said, it just started today. I installed a few things today using apt-get, but I had them before on another Mint KDE installation, and they didn't cause problems. Those things that I installed include Eclipse, OCaml, and FreeCAD, from the FreeCAD ppa. I also removed thunderbird mail using sudo apt-get remove thunderbird. I should also mention that I've had these decorations installed for days without issue until today.
Thank you for your time and patience, as I am a new user and I know that generally people on forums hate new users. But that's who they're for, isn't it?