I have the same issue with the fglrx driver and an ATI Radeon Mobility HD 4650 graphic card.
When I log in from LightDM to Unity 3D, I have a black screen with some small rectangles of the wallpaper. I can click on the session menu and log out, but windows appear with black areas, just like on the screenshot of #3.
I have the same issue with the fglrx driver and an ATI Radeon Mobility HD 4650 graphic card.
When I log in from LightDM to Unity 3D, I have a black screen with some small rectangles of the wallpaper. I can click on the session menu and log out, but windows appear with black areas, just like on the screenshot of #3.
Unity 2D session is working good.