Recently I installed LinCity, a sim-city clone, on Linux Mint. It didn’t run, so I uninstalled it. After uninstalling the package, my minimize, maximize, and close buttons disappeared on all my windows. It wasn’t just that. My mouse cursor became a big “X” and right-click stopped working!
I knew some setting had changed during the uninstall but I wasn’t sure what it was. A quick Google search showed results from 2012 which didn’t seem to apply to my version of Linux Mint. I tried them anyway with no success. Another poster said they had luck re-installing some of the core packages. I tried re-installing all of the GNOME and Cinnamon packages that were already installed. That did nothing.
Eventually under “Preferences” I found the “Desktop Settings” application. In that app, under “Windows” I discovered that my Windows Manager setting was blank. I set it to “Metacity” and bam! everything started working again. I tried switching to Compiz, but then all my buttons disappeared again. Luckily there’s a “Reset Compiz Setttings” button on the same screen. After pressing that my desktop was back to normal.
Not sure why this happened, but hopefully this post helps someone else!