Fix for the centring of the about frames.
See the thread starting at https://mail.gna.org/public/relax-devel/2010-09/msg00007.html (Message-id: <AANLkTin3ADi0T7tnqADj-u76-cF2ndwgKswZ8Fyi5NZO@...>).
Authored by: bugman 2010-09-15
Parent: [r11552]
Child: [r11554]
