Comment 6 for bug 1356892

I'm also experiencing this issue. Currently running 14.04.2 with Compiz enabled on an Gigabyte motherboard intel i7cpu.
The issue happens about once in every session at random times. Mostly when I have 2+ windows open.

The way I fix it is I go the windows list on the bottom panel, right click on the window that is giving me issue, Select minimize then right click the same window and select unminimize and the buttons re-appear