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
}
		return index;
	}
	private void refreshValueTable( )
	{
		if ( valueTable != null && !valueTable.getTable( ).isDisposed( ) )
		{
			valueTable.refresh( );
		}
	}
	private void refreshParameterProperties( )
	{
		if ( selectedParameter == null || selectedParameter == newParameter )
		{
			clearParamProperties( );
			setControlEnabled( false );
			return;
		}
		loading = true;
		setControlEnabled( true );
		paramNameEditor.setText( selectedParameter.getName( ) );
		if ( selectedParameter.getPromptText( ) == null )
		{
			promptText.setText( "" ); 
		}
		else
		{
			promptText.setText( selectedParameter.getPromptText( ) );
		}
		dataTypeChooser.setText( dataType.findChoice( selectedParameter.getDataType( ) )