CTL-ALT-F1
CTL-ALT-F7
This takes you from the graphics environment to a full screen text console and back, which re-initializes the graphics environment. It doesn't affect your running applications.
First reported in 2012.[1] Search for "cursor disappears ubuntu" for the long and broad history of this bug. I see there's been progress on the bug report.[2] Unfortunately, fixing it seems to have broken some other things. But after years of complaints and confusion, effort is being put in on it.
Visualize having to explain this to a CFO whom you're trying to convince to use Linux.
[1] http://askubuntu.com/questions/118001/how-to-restart-only-mi... [2] https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video...
Only holding the power button unreasonably long did anything, and that wasn't anything good.
I was surprised at how many GUI bugs there were in the stacks of the mainstream OS's when I had to work on some in the last few weeks.
If you are competent I recommend moving away from xubuntu, or at least its defaults. Take note of the programs you like and install them on the new system, or note the ones you don't and replace them. Swapping wm's is pretty common.
A tiling wm is not for everyone, and my job doesn't involve much mouse work, however when I have had to use GIMP and Inkscape they have worked pretty much perfectly in their fullscreen beauty.
But yeah. Not for everybody.
Actually I had lots of success editing graphics from command line with ImageMagick. Granted there are lots of things that you need a mouse to do but I was surprised how far I could go with just the command line.