adding arbitrary applet to panel

initially opened here:
http://bugzilla.gnome.org/show_bug.cgi?id=331768

each time i want to add a new application to the gnome panel (click on
"application launcher..." in the "Add to panel" window makes gnome panel
crash)

#3 <signal handler called>
#4 0x7775fbf8 in IA__g_markup_escape_text (
    text=0x8636000 <Address 0x8636000 out of bounds>, length=31)
    at gmarkup.c:1890
#5 0x77762139 in IA__g_markup_vprintf_escaped (
    format=0x80b9784 "<span weight=\"bold\">%s</span>\n%s",
    args=0x7ff0d024
"xÿ_\b\220ÿ_\b°¶\\\bpQM\b°¶\\\b\230Ðð\177Å\034\n\b`Y]\b|
Ðð\177ÜÐð\177:\v~wüÙdw@òdwà]`\bxÐð\177JcXw@òdwà]`\bÔ³{wÜÐð\177`Y]\b\230Ðð\177'÷ø\207xß\\\b0kðw´¶\\\b°¶\\\b\b")
at gmarkup.c:2200
#6 0x77762296 in IA__g_markup_printf_escaped (
    format=0x8636000 <Address 0x8636000 out of bounds>) at gmarkup.c:2257
#7 0x080a170b in panel_addto_make_text (name=<value optimized out>,
    desc=0x85fff90 "Effectue des calculs compliqués")
    at /build/buildd/gnome-panel-2.13.91/./gnome-panel/panel-addto.c:215
#8 0x080a1cc5 in panel_addto_populate_application_model (store=0x85d5960,
    parent=0x7ff0d0dc, app_list=<value optimized out>)
    at /build/buildd/gnome-panel-2.13.91/./gnome-panel/panel-addto.c:623
#9 0x080a1d4d in panel_addto_populate_application_model (store=0x85d5960,
    parent=0x0, app_list=<value optimized out>)
    at /build/buildd/gnome-panel-2.13.91/./gnome-panel/panel-addto.c:639
#10 0x080a2b2e in panel_addto_add_item (dialog=0x84d6ac0, item_info=0x85e5690)
    at /build/buildd/gnome-panel-2.13.91/./gnome-panel/panel-addto.c:663
#11 0x080a2cae in panel_addto_add_launcher (dialog=0x84d6ac0)
    at /build/buildd/gnome-panel-2.13.91/./gnome-panel/panel-addto.c:834
#12 0x777d2663 in IA__g_cclosure_marshal_VOID__VOID (closure=0x84e2f90,
    return_value=0x0, n_param_values=1, param_values=0x7ff0d3dc,
    invocation_hint=0x7ff0d2dc, marshal_data=0x80a2c74) at gmarshal.c:77
#13 0x777c5798 in IA__g_closure_invoke (closure=0x84e2f90,
    return_value=0x8636000, n_param_values=140730368, param_values=0x8636000,
    invocation_hint=0x8636000) at gclosure.c:490
#14 0x777d5715 in signal_emit_unlocked_R (node=0x8137d20, detail=0,
    instance=0x80f64d0, emission_return=0x0, instance_and_params=0x7ff0d3dc)
    at gsignal.c:2438