17.04 unable to select any window

I have a setup that has worked for years with synergy running between a dual headed Ubuntu box (currently running 17.04) and a dual-headed Windows 10 box.

Today I started to see the Ubuntu box get into weird states. The Ubuntu box is the server for synergy. However, the focus would get stuck on the PC. I reboot a few times. I tried leaving the windows box off and not starting synergy. It would work for a little while and then just stop recognizing any windows. I could move the mouse around and could select the start menu, and run things from there but I could not select any windows so I could not interact with them.

Has anyone seen anything like this? If so what did you do?