Bug 315745 Two message pop up when switch from XML source to layout.[01]
UI/org.eclipse.birt.report.designer.ui.lib/src/org/eclipse/birt/report/designer/ui/editors/LibraryLayoutEditorFormPage.java
{
				ReportPlugin.getDefault( )
						.getPreferenceStore( )
						.setValue( ReportPlugin.LIBRARY_WARNING_PREFERENCE,
								MessageDialogWithToggle.NEVER );
			}
		}
		
		
		ModuleHandle newModel = getProvider( ).queryReportModuleHandle( );
		boolean reload = false;
		if ( getStaleType( ) == IPageStaleType.MODEL_RELOAD )
		{
			setModel( null );
			doSave( null );
			reload = true;
		}
		if ( ( newModel != null && getModel( ) != newModel ) || reload )
		{
			Object oldModel = getModel( );
			setModel( newModel );
			rebuildReportDesign( oldModel );
			if ( getModel( ) != null )
			{
				this.getGraphicalViewer( ).setContents( getModel( ) );
				hookModelEventManager( getModel( ) );
				markPageStale( IPageStaleType.NONE );
			}
			updateStackActions( );
		}