Bug 123207 PropertyHandle items cannot be moved down
Use the property handle to move down the item. It seems not work.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/dialogs/PropertyHandleTableViewer.java
data.verticalAlignment = SWT.CENTER;
            btnComposite.setLayoutData(data);
            GridLayout btnLayout = new GridLayout();
            layout.verticalSpacing = 20;
            btnComposite.setLayout(btnLayout);
            
            GridData btnData = new GridData(GridData.CENTER);
            btnData.widthHint = 20;
            btnData.heightHint = 20;
            btnUp = new Button(btnComposite, SWT.ARROW | SWT.UP);
            btnUp.setLayoutData(btnData);
            btnUp.addSelectionListener(new SelectionListener(){
                public void widgetSelected(SelectionEvent e)
                {
                    
                    int index = viewer.getTable( ).getSelectionIndex( );
                    PropertyHandle handle = (PropertyHandle) viewer.getInput();
                    if ( index > 0
                            && handle.getListValue( ) != null
                            && index < handle.getListValue( ).size( ))
                    {
                        viewer.cancelEditing();
                        try
                        {
                            handle.moveItem( index, index -1 );
                        }
                        catch ( PropertyValueException e1 )
                        {
                            ExceptionHandler.handle( e1 );
                        }