X11 now via XQuartz
I tried running Inkscape and it wouldn’t start. It seems that OS X 10.8 (Mountain Lion) doesn’t ship X11 any longer, and you have to use XQuartz.
You’re then forced to log out & log back in. Once that is complete, Inkscape and others work again. This problem doesn’t exist with The GIMP any longer as that is now native. Here’s hoping Inkscape moves with the times too.
