[Freeciv-Dev] (PR#4068) Pressing Help button in Production causes segfault

["Guest" <rt-guest@xxxxxxxxxxxxxx>]

Pressing the Help buttin in the Production tab of a city dialog causes a
segmentation fault.

Current cvs, gtk2 client.

Backtrace:
(gdb) bt
#0  0x401ae723 in gtk_tree_selection_get_selected ()
   from /usr/lib/libgtk-x11-2.0.so.0
#1  0x080a0c83 in help_callback (w=0x8410810, data=0x839af68) at wldlg.c:494
#2  0x4037bd01 in g_cclosure_marshal_VOID__VOID ()
   from /usr/lib/libgobject-2.0.so.0
#3  0x403670c0 in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#4  0x4037b8b4 in signal_emit_unlocked_R () from
/usr/lib/libgobject-2.0.so.0
#5  0x4037a888 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#6  0x40139fdf in gtk_signal_emit () from /usr/lib/libgtk-x11-2.0.so.0
#7  0x4006d9e2 in gtk_button_clicked () from /usr/lib/libgtk-x11-2.0.so.0
#8  0x4006e9ab in gtk_real_button_released () from
/usr/lib/libgtk-x11-2.0.so.0
#9  0x4037bd01 in g_cclosure_marshal_VOID__VOID ()
   from /usr/lib/libgobject-2.0.so.0
#10 0x40367467 in g_type_class_meta_marshal ()
   from /usr/lib/libgobject-2.0.so.0
#11 0x403670c0 in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#12 0x4037b13f in signal_emit_unlocked_R () from
/usr/lib/libgobject-2.0.so.0
#13 0x4037a888 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#14 0x40139fdf in gtk_signal_emit () from /usr/lib/libgtk-x11-2.0.so.0
#15 0x4006d932 in gtk_button_released () from /usr/lib/libgtk-x11-2.0.so.0
#16 0x4006e82b in gtk_button_button_release ()
   from /usr/lib/libgtk-x11-2.0.so.0
#17 0x400f70e4 in _gtk_marshal_BOOLEAN__BOXED ()
   from /usr/lib/libgtk-x11-2.0.so.0
#18 0x40367467 in g_type_class_meta_marshal ()
   from /usr/lib/libgobject-2.0.so.0
#19 0x403670c0 in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#20 0x4037b369 in signal_emit_unlocked_R () from
/usr/lib/libgobject-2.0.so.0
#21 0x4037a689 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#22 0x40139fdf in gtk_signal_emit () from /usr/lib/libgtk-x11-2.0.so.0
#23 0x401dd413 in gtk_widget_event_internal ()
   from /usr/lib/libgtk-x11-2.0.so.0
#24 0x400f6e67 in gtk_propagate_event () from /usr/lib/libgtk-x11-2.0.so.0
#25 0x400f5b45 in gtk_main_do_event () from /usr/lib/libgtk-x11-2.0.so.0
#26 0x402a7f21 in gdk_event_dispatch () from /usr/lib/libgdk-x11-2.0.so.0
#27 0x403c0f65 in g_main_dispatch () from /usr/lib/libglib-2.0.so.0
#28 0x403c1f98 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#29 0x403c22ad in g_main_context_iterate () from /usr/lib/libglib-2.0.so.0
#30 0x403c2a1f in g_main_loop_run () from /usr/lib/libglib-2.0.so.0
#31 0x400f539f in gtk_main () from /usr/lib/libgtk-x11-2.0.so.0
#32 0x0809097b in ui_main (argc=1, argv=0xbffff9b4) at gui_main.c:1123
#33 0x0806612e in main (argc=1, argv=0xbffff9b4) at civclient.c:239
#34 0x420158f7 in __libc_start_main () from /lib/i686/libc.so.6

Kenn