I'm using Ubuntu 16.04 with the MATE desktop (Mate Desktop 1.8.2). (I use Ubuntu 16.04 for work since it's the version running on our server).
This problem only started happening in the last month or so, and now it happens a few times a week: the taskbar at the bottom starts to become graphically corrupted. At first it all appears fine, but doesn't update when I click on a different application. Often it has a sort of wide grey triangle on it, and then usually turns full gray except for the time, which is still accurate, and a desktop icon on the left, which no longer works. I can always fix it by rebooting but i'd prefer to not have to do this.
Despite the graphical problems, it still seems to work - i can click in various different places and it does switch to the different apps.
I've tried this, following this post: https://askubuntu.com/questions/125662/how-to-reset-gnome-panel
dconf reset -f /org/gnome/gnome-panel/
killall gnome-panel
but there is no gnome-panel
process running (I tried kde-panel but that's not running either).
I was able to reset the panel, by doing this:
mate-panel --reset
This didn't fix the problem, it just meant that after I rebooted all of my customisation (just app launcher shortcuts next to the Start button) was gone and I had to set it all up again.
Any ideas anyone, as to what might be causing this and how to address it?