Bug 135465 [smoke]An error occurred when new a casading Parameter
Description: An error occurred when new a casading Parameter Step to reproduce: 1.new a sample db data source and data set 2.New a cascading parameter group, named "gp1", 3.select the data set, then create two cascading parameters, one is row["customernumber"], named p1; the other is row["customername"] Actual result; error message occurred repeatly
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/CascadingParametersDialog.java
Group group = new Group( parent, SWT.NULL );
		group.setText( LABEL_GROUP_GENERAL );
		group.setLayout( new GridLayout( 2, false ) );
		group.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
		Label label = new Label( group, SWT.NULL );
		label.setText( LABEL_CASCADING_PARAMETER_NAME );
		cascadingNameEditor = new Text( group, SWT.BORDER );
		cascadingNameEditor.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
	}
	private void createDynamicParamsPart( Composite parent )
	{
		Composite comp = new Composite( parent, SWT.NULL );
		GridLayout layout = new GridLayout( 3, false );
		layout.marginHeight = 0;
		layout.marginWidth = 0;
		comp.setLayout( layout );
		comp.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
		createLabel( comp, LABEL_DATA_SETS );
		dataSetsCombo = new Combo( comp, SWT.READ_ONLY );
		GridData data = new GridData( );
		data.widthHint = 120;
		dataSetsCombo.setLayoutData( data );
		dataSetsCombo.setItems( getDataSets( ) );
		dataSetsCombo.addSelectionListener( new SelectionAdapter( ) {
			public void widgetSelected( SelectionEvent e )
			{
				dataSet = getDataSet( dataSetsCombo.getText( ) );
				refreshValueTable( );
				updateButtons( );
			}