All of a sudden yesterday, my Linux Mint 18.1 Cinnamon 64bit desktop froze. I used
killall -HUP cinnamon in TTY1 and came back to TTY7 to find a dialog stating that Cinnamon was now in fallback mode and asked if I wished to restart it. I elected not to restart it as I had unsaved work in the session and thought I remembered that this kills all applications running in the GUI environment underneath Cinnamon.
However almost immediately after, the GUI again started to ask weird... The menu changed design; There was no more Close, Minimise, Maximise, etc controls at the top of each window; Pressing Alt+Tab didn't display a list of opening windows; Clicking the windows in the taskbar didn't result in their windows displaying and taking focus; While I could open new applications, the menus in those applications didn't display when clicked. See below for a picture of the screen elements mentioned above.
killall -HUP cinnamon didn't result in any GUI changes/messages this time, so I did some research which all seemed to suggest that Cinnamon needed restarting, so I tried the below commands (despite
ptree stating it was seemingly running), with the seen-below results.
My guess at this point is that there is another component to the GUI system on Linux Mint 18.1 Cinnamon 64bit that draws the missing components that is not currently running, but in searches for what GUI components run in the aforementioned version of Mint, have only been able to find the Panel, Taskbar, Window Manager, and Desktop component names for the Xcfe version (https://forums.linuxmint.com/viewtopic.php?t=71858).
Can anyone help me at least restore my ability to save the work in the open programs, or bring back full functionality of the GUI environment this time which I am sure will be helpful for future occurrences also?