Mousepad works fine with GTK+ 2.10.6. However, as soon as GTK+ is upgraded from 2.6.10 to 2.16.7 (the latest GTK+ version), Mousepad segfaults, even after a recompilation with GTK+ 2.10.7 installed.

$ pkg-config --modversion glib-2.0
2.12.7
bash-3.1$ pkg-config --modversion gtk+-2.0
2.10.7
$ gdb mousepad
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This GDB was configured as "i486-slackware-linux"...Using host libthread_db library "/lib/tls/libthread_db.so.1".

(gdb) run
Starting program: /usr/bin/mousepad 
[Thread debugging using libthread_db enabled]
[New Thread -1218914624 (LWP 10872)]

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1218914624 (LWP 10872)]
0xb7b2a7ef in gdk_drawable_get_screen () from /usr/lib/libgdk-x11-2.0.so.0
$