[glom/glom-1-26] Add a small null-pointer check.

[Murray Cumming <murrayc src gnome org>]

commit 5370778231051fbef9a3d0eb39beb333c886b528
Author: Murray Cumming <murrayc murrayc com>
Date:   Tue Jun 17 12:37:36 2014 +0200

    Add a small null-pointer check.

 .../layout_item_dialogs/dialog_field_layout.cc     |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/glom/mode_design/layout/layout_item_dialogs/dialog_field_layout.cc 
b/glom/mode_design/layout/layout_item_dialogs/dialog_field_layout.cc
index a874fbf..21fa116 100644
--- a/glom/mode_design/layout/layout_item_dialogs/dialog_field_layout.cc
+++ b/glom/mode_design/layout/layout_item_dialogs/dialog_field_layout.cc
@@ -56,7 +56,7 @@ Dialog_FieldLayout::Dialog_FieldLayout(BaseObjectType* cobject, const Glib::RefP
 
   //Get the formatting stuff:
   Utils::get_glade_child_widget_derived_with_warning(m_box_formatting);
-  if(m_box_formatting)
+  if(m_box_formatting && m_box_formatting_placeholder)
   {
     m_box_formatting_placeholder->pack_start(*m_box_formatting);
     add_view(m_box_formatting);