Comment 6 for bug 1300892

Seeing the same thing on 16.04.2 32bit with i5-4460 8Gb and a GTX 960.

Present with all NVidia proprietary drivers (up to 381.13), not present with nouveau driver (but that has other issues.)

Restarting unity with "unity --replace" on the command line usually makes it go (may sometimes take a couple of tries.)

NVidia GPUs are extremely common and the Nouveau driver is terribly buggy and crash prone, if this is genuinely a unity bug then I don't think it's reasonable to triage this as low as it makes the desktop essential unusable for work purposes and I suspect an awful lot more people are experiencing this bug than realise it's cause. (It took me far too long to find this bug report myself and I've been battling with this for months.)