Steps to reproduce:
1. On OpenSolaris PolicyKit is not available, thus compiling clock applet the
   source file set-timezone-dummy.c is used, you a version of clock applet    
   compiled in this manner
2. Add this clock applet to your panel
3. If you don't have locations add some via Preferences, locations
4. Once locations added, browse over them, once mouse is located to the left 
   of a non home location, a "Set" button displays, select this button for 
   one of the locations.
5. Clock applet will then crash.


Stack trace:
Stack traces vary, as this is a race condition/thread issue, here's an example 
either way:

current thread: t@1
  [1] g_slice_alloc(0x10), at 0xfed9f907 
  [2] g_data_set_internal(0x82418b0, 0x2d6, 0xfebd32ac, 0x0, 0x0, 0xfee2a5d4,
0x80439d8, 0xfed6b90e), at 0xfed6b52b 
  [3] g_datalist_id_set_data_full(0x82418b0, 0x2d6, 0xfebd32ac, 0x0), at
0xfed6b9f7 
  [4] g_object_set_qdata(0x82418a8, 0x2d6, 0xfebd32ac, 0xfea0057c), at
0xfec765c0 
  [5] mark_visited(0x82418a8), at 0xfea0059b 
  [6] add_widget_to_closure(0x82418a8, 0x2, 0x8043aec, 0x8043ae8), at
0xfea006c7 
  [7] add_group_to_closure(0x86af4a0, 0x2, 0x8043aec, 0x8043ae8), at 0xfea00679 
  [8] add_widget_to_closure(0x8253b50, 0x2, 0x8043aec), at 0xfea00710 
  [9] compute_dimension(0x8253b50, 0x2, 0x8043b28, 0xfea01788), at 0xfea0149b 
  [10] _gtk_size_group_compute_requisition(0x8253b50, 0x8043b88, 0x8043b58,
0xfeab5e4a), at 0xfea017b6 
  [11] gtk_widget_size_request(0x8253b50, 0x8043b88, 0x8043ba8, 0xfe8c785b), at
0xfeab5e8f 
  [12] gtk_box_size_request(0x825a1d0, 0x825a1ec, 0x80c0588, 0xfec88cd2), at
0xfe8c7884 
  [13] g_cclosure_marshal_VOID__BOXED(0x80e4a70, 0x0, 0x2, 0x8228af0,
0x8043d68, 0xfe8c77ec, 0xd, 0xfec6f87c), at 0xfec88d41 
  [14] g_type_class_meta_marshal(0x80e4a70, 0x0, 0x2, 0x8228af0, 0x8043d68,
0x7c, 0x4000800d, 0xfec6f4fe), at 0xfec6f8b6 
  [15] g_closure_invoke(0x80e4a70, 0x0, 0x2, 0x8228af0, 0x8043d68, 0x825a1d0,
0x8043ce8, 0xfec863e9), at 0xfec6f5a1 
  [16] signal_emit_unlocked_R(0x80bc650, 0x0, 0x825a1d0, 0x0, 0x8228af0,
0x825a1d0, 0x8043e60, 0x8000000), at 0xfec86c97 
  [17] g_signal_emit_valist(0x825a1d0, 0xf, 0x0, 0x8043f68), at 0xfec85fc8 
  [18] g_signal_emit_by_name(0x825a1d0, 0xfebd331c, 0x825a1ec, 0xfea01405), at
0xfec86322 
  [19] do_size_request(0x825a1d0, 0xfec03f78, 0x8043f98, 0xfea01788), at
0xfea01439 
  [20] _gtk_size_group_compute_requisition(0x825a1d0, 0x8043ff8, 0x8043fc8,
0xfeab5e4a), at 0xfea017d2 
  [21] gtk_widget_size_request(0x825a1d0, 0x8043ff8, 0x8044018, 0xfe8c785b), at
0xfeab5e8f 
  [22] gtk_box_size_request(0x825a178, 0x825a194, 0x80c0588, 0xfec88cd2), at
0xfe8c7884 
  [23] g_cclosure_marshal_VOID__BOXED(0x80e4a70, 0x0, 0x2, 0x826d678,
0x80441d8, 0xfe8c77ec, 0xc, 0xfec6f87c), at 0xfec88d41 
  [24] g_type_class_meta_marshal(0x80e4a70, 0x0, 0x2, 0x826d678, 0x80441d8,
0x7c, 0x4000800c, 0xfec6f4fe), at 0xfec6f8b6 
  [25] g_closure_invoke(0x80e4a70, 0x0, 0x2, 0x826d678, 0x80441d8, 0x825a178,
0x8044158, 0xfec863e9), at 0xfec6f5a1 


Other information:
Setting timezone is not supported on this system as PolicyKit is not available
to determine if allowed or not.

Thus in set-timezone-dummy.c:set_system_timezone_async(), an Error structure
is created and this is passed to the referenced callback, which in this case is
make_current_cb().

Just after calliing the callback(), the error strut is free'd, however
make_current_cb() attempts to use this struct to display a warning dialog
after which it frees the error structure anyway, this the race condition.

Solution is to remove the g_error_free() call from set_system_timezone_async(), 
and allow make_current_cb() to free it instead.