Alberts, can you do anything with screen blinking when switching
windows? For example,
(1) Hold Alt key
(2) Press Tab key
(3) Press Tab key again
(4) Release Alt key
Right after (3) the screen will blink. If you repeat (3) several
times, the screen will blink every time you do that.
I can reproduce this on both Debian and Ubuntu, with different themes
/ GNOME versions / etc. This did not happen with Gtk 2 version.