After upgrading my Swiftfox from 3.5.3 to 3.5.4-1 it was Problems Galore.
Clicking the pretty swiftfox icon didnt work and typing `swiftfox` from the terminal (/usr/bin/swiftfox which is a script that comes with the installation) gave me
/usr/lib/swiftfox/swiftfox-bin: symbol lookup error: /usr/lib/swiftfox/libxul.so: undefined symbol: gdk_x11_window_get_drawable_impl
sudo aptitude install xulrunner-1.9.1
cd /usr/lib/swiftfoxsudo mv libxul.so libxul.so.orisudo ln -s ../xulrunner-1.9.1.3/libxul.so .