Bug 130495 Get rid of SessionHandleAdapter
Now, we use SessionHandleAdapter to keep current active report deisng. That's a bad practive for editor swith and rebuild will cuase lots of problmes. Need find way to replace it.
UI/org.eclipse.birt.report.designer.ui.editors.schematic/src/org/eclipse/birt/report/designer/ui/editors/pages/ReportLayoutEditorFormPage.java
.getReportDesignHandle( );
		if ( model != null && getModel( ) != model )
		{
			Object oldModel = getModel( );
			setModel( model );
			rebuildReportDesign( oldModel );
			if ( getModel( ) != null )
			{
				this.getGraphicalViewer( ).setContents( getModel( ) );
				markPageStale( IPageStaleType.NONE );
			}
			updateStackActions( );
		}
		return true;
	}
	/**
	 * Rebuild report design model.
	 * 
	 * @param oldModel
	 */
	protected void rebuildReportDesign( Object oldModel )
	{
		
		WrapperCommandStack stack = (WrapperCommandStack) getCommandStack( );
		if ( stack != null )
		{
			stack.removeCommandStackListener( getCommandStackListener( ) );
			stack.setActivityStack( getModel( ).getCommandStack( ) );
			stack.addCommandStackListener( getCommandStackListener( ) );
		}