Comment # 1 on bug 1206233 from Dominique Leuenberger

I can reproduce this on my GNOME:Next based workstation.

simply calling gnome-control-center wifi does not show the panel, but a bunch
of crits on the console

(gnome-control-center:18361): Gtk-CRITICAL **: 15:56:37.151: Error building
template class 'CcWifiPanel' for an instance of type 'CcWifiPanel': .:0:0
Invalid property: GtkBox.expand

(gnome-control-center:18361): Gtk-CRITICAL **: 15:56:37.154:
gtk_stack_add_named: assertion 'GTK_IS_STACK (stack)' failed

(gnome-control-center:18361): Gtk-CRITICAL **: 15:56:37.154:
gtk_stack_add_named: assertion 'GTK_IS_STACK (stack)' failed

(gnome-control-center:18361): Gtk-CRITICAL **: 15:56:37.154:
gtk_stack_set_visible_child_name: assertion 'GTK_IS_STACK (stack)' failed

(gnome-control-center:18361): Gtk-CRITICAL **: 15:56:37.155:
gtk_stack_add_titled: assertion 'GTK_IS_STACK (stack)' failed

(gnome-control-center:18361): cc-list-row-CRITICAL **: 15:56:37.157:
cc_list_row_get_active: assertion 'CC_IS_LIST_ROW (self)' failed

(gnome-control-center:18361): Gtk-CRITICAL **: 15:56:37.157:
gtk_stack_set_visible_child_name: assertion 'GTK_IS_STACK (stack)' failed

(gnome-control-center:18361): Gtk-CRITICAL **: 15:56:37.458:
gtk_widget_set_visible: assertion 'GTK_IS_WIDGET (widget)' failed

(gnome-control-center:18361): cc-list-row-CRITICAL **: 15:56:37.458:
cc_list_row_get_active: assertion 'CC_IS_LIST_ROW (self)' failed

(gnome-control-center:18361): cc-list-row-CRITICAL **: 15:56:37.458:
cc_list_row_set_switch_sensitive: assertion 'CC_IS_LIST_ROW (self)' failed

(gnome-control-center:18361): cc-list-row-CRITICAL **: 15:56:37.461:
cc_list_row_get_active: assertion 'CC_IS_LIST_ROW (self)' failed

(gnome-control-center:18361): Gtk-CRITICAL **: 15:56:37.461:
gtk_stack_set_visible_child_name: assertion 'GTK_IS_STACK (stack)' failed