Gnome 3 - Strange black areas inside windows

I'm facing a strange issue after upgrading from Ubuntu 13.10 to 14.04 (well, technically, it wasn't an upgrade, as the network upgrade failed and I had to do a clean install). On many application windows, there are black areas, sometimes taking up the entire background of the window, sometimes only portions of it. This issue occurs on all GTK+ and Window themes.

I'm using GNOME 3.12.2, running on an ATI Mobility Radeon HD 4570 graphics card.

Screenshot 1

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Screenshot 3


Try running this in a terminal:

gsettings set com.canonical.desktop.interface scrollbar-mode normal