OpenGL stop repainting and app may crash on close after disconnect of one of monitors (linux)

Ubuntu 14.04 lts + Qt 5.3.2. Can be reproduced by description.

Reproduce steps (at last I've test with Qt 5.2.0):

• start QtCreator
• open "hellogl" example (or any other OpenGL example)
• run it
• place app to the monitor, that you want to disconnect (in my case: laptop(1366x768) + external monitor (1920x1080), and app on the laptop's display)
• Open System settings -> Displays
• switch of monitor with app (in my case laptop) and apply changes
• after that OpenGL's scene is black and may be crash on application close

I can reproduce with external display too, but chance isn't 100 %. Need to repeat a few times.