[ forwarded from http://bugs.debian.org/407470 ]

It seems that in when run in x11vnc, GTK is unable to get the physical screen dimensions, and returns 0. However the font properties dialog uses them to extract the DPI value.

The following gdb session explains all:

0x0804e645 in cb_show_details (button=0x807b5f0, parent=0x80c2010)
    at /home/chris/src/gnome-control-center/control-center-2.14.2/./capplets/font/main.c:856
856                     dpi = floor ((gdk_screen_width () / gdk_screen_width_mm () +
(gdb) print gdk_screen_height()
$1 = 864
(gdb) print gdk_screen_height_mm()
$2 = 0
(gdb) print gdk_screen_width()
$3 = 1152
(gdb) print gdk_screen_width_mm()
$4 = 0
(gdb) where

+ Trace 103641

Apparently, the bug is still present in HEAD. This could be fixed by adding a check that these values are non-zero.