gnome-file-types-properties crashes if user attempts to add a service when
an existing file type is selected.

To Recreate
------------
(1) Start gnome-file-types-properties (select "Applications->Desktop
Preferences->Advanced->File Types and Programs")

(2) Select an existing file type and click the "Add a service" button =>
gnome-file-types-properties will crash.


*Will attach file containing truss output.


*The following debug was written to terminal when run thorugh dbx:

t@1 (l@1) signal SEGV (no mapping at the fault address) in
program_changed_cb dbx: warning: can't find file
"/gnome/2.0/nightly/forte/debug/src-2.0n-290402/gnome-control-center/capplets/file-types/service-edit-dialog.o"
at 0x2dc7c
0x0002dc7c: program_changed_cb+0x01ec:	ld	[%l0 + 0x8], %l0
dbx: warning: can't find file
"/gnome/2.0/nightly/forte/debug/src-2.0n-290402/glib/gobject/gsignal.lo"
dbx: warning: can't find file
"/gnome/2.0/nightly/forte/debug/src-2.0n-290402/glib/gobject/gclosure.lo"
dbx: warning: can't find file
"/gnome/2.0/nightly/forte/debug/src-2.0n-290402/gtk-multihead/gtk/gtkoptionmenu.lo"
dbx: warning: can't find file
"/gnome/2.0/nightly/forte/debug/src-2.0n-290402/glib/gobject/gobject.lo"
dbx: warning: can't find file
"/gnome/2.0/nightly/forte/debug/src-2.0n-290402/gtk-multihead/gtk/gtksignal.lo"
dbx: warning: can't find file
"/gnome/2.0/nightly/forte/debug/src-2.0n-290402/gtk-multihead/gtk/gtkbutton.lo"
dbx: warning: can't find file
"/gnome/2.0/nightly/forte/debug/src-2.0n-290402/gtk-multihead/gtk/gtkmarshalers.lo"
dbx: warning: can't find file
"/gnome/2.0/nightly/forte/debug/src-2.0n-290402/gtk-multihead/gtk/gtkwidget.lo"
dbx: warning: can't find file
"/gnome/2.0/nightly/forte/debug/src-2.0n-290402/gtk-multihead/gtk/gtkmain.lo"
dbx: warning: can't find file
"/gnome/2.0/nightly/forte/debug/src-2.0n-290402/gtk-multihead/gdk/x11/.libs/libgdk-x11.al(gdkevents-x11.lo)"
dbx: warning: can't find file
"/gnome/2.0/nightly/forte/debug/src-2.0n-290402/glib/glib/gmain.lo"

------------------------------------------------------------------------

*The following is stack output:

14858:	gnome-file-types-properties
-----------------  lwp# 1 / thread# 1  --------------------
 fdd1bc68 waitid   (0, 3a1d, ffbeca38, 3)
 fdcd6038 _waitpid (0, ffbecb40, 0, ffbecb40, 0, 0) + 60
 ff15ae34 waitpid  (b, ffbed018, ffbecd60, ff16e000, 56640, 56630) + 34
 ff15905c __libthread_segvhdlr (b, ffbed018, ffbecd60, ff16e000, b, 0) + e4
 ff15bbcc __sighndlr (b, ffbed018, ffbecd60, ff158f78, 56640, 56630) + c
 ff1583b8 sigacthandler (b, 565a8, 0, 0, 0, ff16e000) + 704
 --- called from signal handler with signal 11 (SIGSEGV) ---
 0002dc7c program_changed_cb (28a8c0, 2a1538, 1, 1, 74478, fe5caa08) + 1ec
 fdec9198 g_cclosure_marshal_VOID__VOID (291b60, 0, 2a1538, 28a8c0, 291b60,
2da90) + 150
 fdea3080 g_closure_invoke (291b60, 0, 1, ffbed3e0, ffbed2b4, ffbed2c9) +
278
 fdec8598 signal_emit_unlocked_R (2a0df0, 0, 2a1538, 0, ffbed3e0, ffbed3d1)
+ b70
 fdec7174 g_signal_emit_valist (2a1538, af, 0, ffbed620, ff3e2668,
fe422480) + b44
 fdec75ec g_signal_emit (2a1538, af, 0, 28cc00, 0, 0) + 64
 fe5cbac8 gtk_option_menu_changed (2a1538, 2a155c, fe5cbcf0, 0, 2a1538, 0)
+ d8
 fe5cc020 gtk_option_menu_update_contents (2a1538, fe76ff40, fe5cc1f8, 0,
2a1538, 0) + 288
 fe5c9dd4 gtk_option_menu_set_menu (2a1538, 294538, 1, 0, 0, ffbed881) +
264
 0002cfb0 setup_add_dialog (28a8c0, 0, 0, ffffffff, 0, 0) + 90
 0002c658 service_edit_dialog_set_prop (28a8c0, 3, ffbed868, 1cf4e8, 0,
220618) + 208
 fdea85ec object_set_property (28a8c0, 1cf4e8, 28c580, 5ded4, 0, 3a) + 234
 fdea95b4 g_object_constructor (226f58, 2, 28a890, 1, 0, 3a) + d4
 fdea8cdc g_object_newv (226f58, 2, 28c558, 0, 0, 28c599) + 57c
 fdea9428 g_object_new_valist (226f58, 3bdf8, ffbedb54, 0, ff3e2668, 1a308)
+ 5d8
 fdea8720 g_object_new (226f58, 3bdf8, a8e38, 4f624, 1, 0) + e0
 0002cd38 service_add_dialog_new (a8e38, 875d8, ffffffff, 7efefeff, 7cb50,
28bd9b) + 38
 0001e754 add_service_cb (90bb8, 7f898, 1, 0, 0, 0) + 54
 fdec9198 g_cclosure_marshal_VOID__VOID (1a2cf0, 0, 7f898, 90bb8, 1a2cf0,
1e700) + 150
 fdea3080 g_closure_invoke (1a2cf0, 0, 1, ffbedeb8, ffbedd8c, ffbedda1) +
278
 fdec8598 signal_emit_unlocked_R (79ab8, 0, 90bb8, 0, ffbedeb8, 0) + b70
 fdec7174 g_signal_emit_valist (90bb8, 4d, 0, ffbee0f4, ff3e2668, fe41e07c)
+ b44
 fe6122a8 gtk_signal_emit (90bb8, 4d, 2249c0, ffbeed38, 0, 15d2c) + f0
 fe49ab24 gtk_button_clicked (90bb8, 59964, 1, 0, 0, 0) + d4
 fe49c87c gtk_real_button_released (90bb8, 71c98, 1, 0, 0, ffbee991) + a4
 fdec9198 g_cclosure_marshal_VOID__VOID (782c0, 0, 71c98, 90bb8, 782c0,
fe49c7d8) + 150
 fdea3600 g_type_class_meta_marshal (782c0, 0, 1, ffbee4c0, ffbee394, 1a4)
+ b0
 fdea3080 g_closure_invoke (782c0, 0, 1, ffbee4c0, ffbee394, ffbee3a9) +
278
 fdec7ffc signal_emit_unlocked_R (79f68, 0, 90bb8, 0, ffbee4c0, 0) + 5d4
 fdec7174 g_signal_emit_valist (90bb8, 4c, 0, ffbee6fc, ff3e2668, fe41f702)
+ b44
 fe6122a8 gtk_signal_emit (90bb8, 4c, 2249c0, ffbeed38, 0, 15d2c) + f0
 fe49aa24 gtk_button_released (90bb8, 59964, 1, 0, 0, 0) + d4
 fe49c450 gtk_button_button_release (90bb8, 2249c0, 71ab8, 0, 0, ffbee991)
+ 50
 fe592bd0 _gtk_marshal_BOOLEAN__BOXED (74898, ffbee978, 71ab8, 90bb8,
74898, fe49c400) + 1d8
 fdea3600 g_type_class_meta_marshal (74898, ffbee978, 2, ffbeead8,
ffbee9ac, b4) + b0
 fdea3080 g_closure_invoke (74898, ffbee978, 2, ffbeead8, ffbee9ac,
ffbee9c1) + 278
 fdec885c signal_emit_unlocked_R (736c8, 0, 90bb8, ffbeeaa0, ffbeead8,
ffbeeb09) + e34
 fdec71fc g_signal_emit_valist (90bb8, 21, 0, ffbeed14, 0, fe42237e) + bcc
 fe6122a8 gtk_signal_emit (90bb8, 21, 2249c0, ffbeed38, 0, 15d2c) + f0
 fe73054c gtk_widget_event_internal (90bb8, 2249c0, 1, 0, 0, 0) + 364
 fe72fefc gtk_widget_event (90bb8, 2249c0, ffbeee04, 8, 0, 5000028) + 1b4
 fe592478 gtk_propagate_event (90bb8, 2249c0, ffbeee30, 0, 0, 0) + 2d8
 fe58fd9c gtk_main_do_event (2249c0, 0, 0, 0, 0, 0) + 4ac
 feb6bc94 gdk_event_dispatch (67e50, 0, 0, 0, 0, 0) + 11c
 fdde0370 g_main_dispatch (67e98, 0, 0, 2, 17998, 0) + 270
 fdde2328 g_main_context_dispatch (67e98, 0, 226210, 7, 7, fe42237e) + c8
 fdde2a88 g_main_context_iterate (67e98, 1, 1, 57690, ff3e2668, 15d2c) +
6b8
 fdde3ab0 g_main_loop_run (220f58, 220f58, 1ec58, 0, 0, 0) + 5c0
 fe58eaf0 gtk_main (8ba10, 3a104, ff06b928, 1, ffbef27c, 0) + 1c0
 0001f3b8 main	   (1, ffbef27c, ffbef284, 4e000, 0, 0) + 180
 0001e350 _start   (0, 0, 0, 0, 0, 0) + 108
-----------------  lwp# 2 / thread# 2  --------------------
 fdd1b048 signotifywait ()
 ff14e8f0 _dynamiclwps (ff16e000, 5a, 0, 0, ffbeed54, 0) + 1c
 ff151b98 thr_yield (0, 0, 0, 0, 0, 0) + 8c
-----------------  lwp# 3  --------------------------------
 fdd18bec door	   (0, 0, 0, 0, fdf25d18, 4)
 ff14a484 _lwp_start (0, 0, 0, 0, 0, 0) + 18
-----------------  lwp# 4  --------------------------------
 fdd1b688 lwp_cond_wait (ff1755a0, ff1755b0, fdc23c48)
 fdd12fc8 _lwp_cond_timedwait (0, 3cce72d8, fdc23cb0, ff1755a0, ff1755b0,
0) + 98
 ff148e34 _age	   (ff16ed98, ff16ed9c, ff16e000, 3, ff16e000, 1) + 94
 ff14a484 _lwp_start (fdc23d78, 0, 4000, fdc0fc34, 0, 0) + 18
 ff151b98 thr_yield (0, 0, 0, 0, 0, 0) + 8c
--------------------------  thread# 3  --------------------
 ff14d958 _reap_wait (ff172a08, 20984, 0, ff16e000, 0, 0) + 38
 ff14d6b0 _reaper  (ff16ee30, ff174770, ff172a08, ff16ee08, 1, fe400000) +
38
 ff15bad0 _thread_start (0, 0, 0, 0, 0, 0) + 40