Now and then, I'll unlock my computer and see this:
You can see in the bottom-right corner that when I open the calendar, nothing is shown. This is true for most applications.
Now look at the bottom-left:
The fonts used in the MATE toolbar are, unlike most applications, just mostly invisible! They have changed color from white to a dark, translucent color that blends in with the rest of the panel.
What could possibly be causing this? A reboot fixes it, but I'd like to ensure that it doesn't happen again.
I am running Ubuntu 16.04 64-bit. I have upgraded from Ubuntu 14.04 64-bit.
Before you ask, I do not have a graphics card. I have integrated graphics:
$ lspci | grep VGA
00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller (rev 06)
