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
}
		else
		{
			IChoice choice = dataType.findChoiceByDisplayName( dataTypeChooser.getText( ) );
			type = choice.getName( );
		}
		return type;
	}
	/**
	 * Gets the internal name of the control type from the display name
	 */
	private String getSelectedDisplayType( )
	{
		String displayText = displayTypeChooser.getText( );
		if ( displayText.length( ) == 0 )
		{
			return null;
		}
		if ( DISPLAY_NAME_CONTROL_COMBO.equals( displayText ) )
		{
			return PARAM_CONTROL_COMBO;
		}
		if ( DISPLAY_NAME_CONTROL_LIST.equals( displayText ) )
		{
			return PARAM_CONTROL_LIST;
		}
		return null;
	}
	private void popupFormatBuilder( boolean refresh )
	{