Hardware acceleration was disabled. I've enabled it and now I don't have the problem anymore. It seems counter intuitive but I'll take what I can get. Thanks for the pointer!

I have a Dell Studio 15 that I recently upgraded to the 14.04LTS release of Ubuntu. After the upgrade, I noticed a very annoying problem with Opera (12.16, x86_64, 3.13.0-32-generic). Regions of the Opera window don't always get painted. For example, the address and bookmarks bars show my desktop background, though if I know where to click, the controls at that location do work. Menus don't always show up or are missing pieces. Even Web page contents often are incomplete.

Over time, I've noticed a few other factors. If I move the entire window, its contents are correctly repainted. Minimizing and restoring messes it up again. It doesn't have this problem after a reboot. It's only after I suspend the OS by closing and reopening the lid that it starts acting up. If Chrome is running, even minimized, Opera behaves. I have not had this trouble with any other applications, only Opera. I've made sure that I'm using the very latest graphics drivers from Intel, though it was using a non-accelerated driver before and Opera's behavior was the same.