Bug 163271 Cascading parameter dialog - Changing from multiple to single dataset does not work
Steps to reproduce - - Create a new cascading parameter group - Select multiple dataset - define parameter country and associate it with datasetCountry - define parameter state and associate with datasetSate Now try to change from multiple dataset to single dataset. The second dataset still shows up and also the report design file is wrong. The single dataset should be saved ast he cascading parameter group level.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/GetParameterDefinitionTask.java
*/
	public Collection getSelectionListForCascadingGroup(
			String parameterGroupName, Object[] groupKeyValues )
	{
		CascadingParameterGroupHandle parameterGroup = getCascadingParameterGroup( parameterGroupName );
		if ( parameterGroup == null )
			return Collections.EMPTY_LIST;
		SlotHandle slotHandle = parameterGroup.getParameters( );
		if ( groupKeyValues.length >= slotHandle.getCount( ) )
		{
			return Collections.EMPTY_LIST;
		}
		for ( int i = 0; i < groupKeyValues.length; i++ )
		{
			String parameterName = (( ScalarParameterHandle ) slotHandle.get( i )).getName( );
			setParameterValue( parameterName, groupKeyValues[ i ] );
		}
		ScalarParameterHandle requestedParam = (ScalarParameterHandle) slotHandle
				.get( groupKeyValues.length ); 
		
		
		if ( requestedParam == null )
		{
			return Collections.EMPTY_LIST;
		}
		return this.getSelectionList( requestedParam.getName( ) );
	}
	private Collection getChoicesFromParameterGroup( ScalarParameterHandle parameter, Object[] groupKeyValues )
	{
		assert isCascadingParameter( parameter );