I was installing a lot of packages attempting to get a USB 3.0 HDMI video card working, but at some point during the process, I lost the ability to grab window borders, or use the minimize, maximize, close buttons. When hoving over the title bar, the mouse goes form a the default pointer to a the text select cursor.

Clicking links and writing text within my browser still works, but is slow and inconsistent.

I tried removing the modules of the new graphics card, and also tried rebooting, neither work. However upon log-in there's some screen tearing before the mouse pointer comes up.

I googled around and found a suggestion that kwin might not be installed and sure enough it wasn't. After installing with apt install kwin and then running kwin things seemed fixed.

However sever hours later I started having the same problem again, this time it coincided with my pushing f12 to launch yakuake. Yakuake failed to appear, and I was no longer able to grab title bars or click to close or min/maximize my windows.

After playing around a bit, I noticed the problem would go away if I pressed F12 again. Thus it seems like there's a ghost instance of Yakuake running.

What is happening? How do I fix it?