segfault in gtk_main_iteration()

[gh6 macs hw ac uk]

package: gtk+
version: 1.2.0
os: debian woody 3.0
x-windows: 4.4.0
glibc_2.2.5-11.2


i'm using gtk1.2 and get a segfault in gtk_main_iteration() while waiting
for some user input:

while(next_step!=1)
        gtk_main_iteration();

according to the backtrace (see below) the main function trys to update a
text widget which i create before

running the while loop. the strange thing is that if i create the window
with the text widget short before

running the while loop the program segfaults. if i create the window in an
earlier stage of the program

everything works fine. could this be a bug in gtk? would be greatful for
any ideas or advices...

Program received signal SIGSEGV, Segmentation fault.
0x400eed44 in gtk_text_forward_delete () from /usr/lib/libgtk-1.2.so.0
(gdb) bt
#0  0x400eed44 in gtk_text_forward_delete () from /usr/lib/libgtk-1.2.so.0
#1  0x400f1f8f in gtk_text_forward_delete () from /usr/lib/libgtk-1.2.so.0
#2  0x400f26d8 in gtk_text_forward_delete () from /usr/lib/libgtk-1.2.so.0
#3  0x400ebc6b in gtk_text_forward_delete () from /usr/lib/libgtk-1.2.so.0
#4  0x400a7e3f in gtk_marshal_BOOL__POINTER () from /usr/lib/libgtk-1.2.so.0
#5  0x400d7013 in gtk_signal_set_funcs () from /usr/lib/libgtk-1.2.so.0
#6  0x400d50b3 in gtk_signal_emit () from /usr/lib/libgtk-1.2.so.0
#7  0x4010bacb in gtk_widget_event () from /usr/lib/libgtk-1.2.so.0
#8  0x400a6f8b in gtk_main_do_event () from /usr/lib/libgtk-1.2.so.0
#9  0x40155457 in gdk_wm_protocols_filter () from /usr/lib/libgdk-1.2.so.0
#10 0x401864d8 in g_get_current_time () from /usr/lib/libglib-1.2.so.0
#11 0x40186ae3 in g_get_current_time () from /usr/lib/libglib-1.2.so.0
#12 0x40186b95 in g_main_iteration () from /usr/lib/libglib-1.2.so.0
#13 0x400a6a4a in gtk_main_iteration () from /usr/lib/libgtk-1.2.so.0
#14 0x0804dffc in halt (mode=1) at execute.c:1550
#15 0x0804d369 in execute_program (vec=0x80a6ca8, input=0xbfffee64)
    at execute.c:876
#16 0x0804c5fe in process_files (the_program=0x80a6ca8, argv=0x805c4e8)
    at execute.c:243
#17 0x0804af77 in sed_main (argc=3, argv=0x805c4e0) at sed.c:208
#18 0x0804fbaa in edit_from_command (w=0x0) at mainframe.c:597
#19 0x400a81b5 in gtk_marshal_NONE__NONE () from /usr/lib/libgtk-1.2.so.0
#20 0x400d7b6c in gtk_signal_remove_emission_hook ()
   from /usr/lib/libgtk-1.2.so.0
#21 0x400d6fd5 in gtk_signal_set_funcs () from /usr/lib/libgtk-1.2.so.0
#22 0x400d50b3 in gtk_signal_emit () from /usr/lib/libgtk-1.2.so.0
#23 0x4010bc0e in gtk_widget_activate () from /usr/lib/libgtk-1.2.so.0
#24 0x400b0614 in gtk_menu_shell_activate_item () from
/usr/lib/libgtk-1.2.so.0
#25 0x400af89a in gtk_menu_shell_deactivate () from /usr/lib/libgtk-1.2.so.0
#26 0x400a7e3f in gtk_marshal_BOOL__POINTER () from /usr/lib/libgtk-1.2.so.0
#27 0x400d7013 in gtk_signal_set_funcs () from /usr/lib/libgtk-1.2.so.0
#28 0x400d50b3 in gtk_signal_emit () from /usr/lib/libgtk-1.2.so.0
#29 0x4010bacb in gtk_widget_event () from /usr/lib/libgtk-1.2.so.0
#30 0x400a7d85 in gtk_propagate_event () from /usr/lib/libgtk-1.2.so.0
#31 0x400a6eee in gtk_main_do_event () from /usr/lib/libgtk-1.2.so.0
#32 0x40155457 in gdk_wm_protocols_filter () from /usr/lib/libgdk-1.2.so.0
#33 0x401864d8 in g_get_current_time () from /usr/lib/libglib-1.2.so.0
#34 0x40186ae3 in g_get_current_time () from /usr/lib/libglib-1.2.so.0
#35 0x40186c7c in g_main_run () from /usr/lib/libglib-1.2.so.0
#36 0x400a67e7 in gtk_main () from /usr/lib/libgtk-1.2.so.0
#37 0x08051cc4 in display_mainframe (argc=1, argv=0xbffffd94)
    at mainframe.c:1088
#38 0x0804ad84 in main (argc=1, argv=0xbffffd94) at xsed.c:9