Bug 120503 Cascading Parameter can not drop into layout
Details: Cascading Parameter can not drop into layout Step: 1.Open a report design and Create a Sample Data Source and data set by "select * from CLASSICMODELS.CUSTOMERS" 2.New a cascading parameter and create CUSTOMERSNUMBER and CUSTOMERSNAME in parameter named number and name. Press OK 3.Drop parameter name into layout. Actual results: The parameter in Cascading Parameter Group can not drop to layout
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/util/DEUtil.java
return "DataSource";
		List methods = handle.getDefn( ).getLocalMethods( );
		for ( Iterator iter = methods.iterator( ); iter.hasNext( ); )
		{
			IMethodInfo method = ( (ElementPropertyDefn) iter.next( ) )
					.getMethodInfo( );
			if ( method.getName( ).equals( methodName ) )
			{
				Iterator argumentListIterator = method.argumentListIterator( );
				if ( argumentListIterator.hasNext( ) )
				{
					IArgumentInfoList argumentInfoList = (IArgumentInfoList) argumentListIterator
							.next( );
					int i = 0;
					for ( Iterator iterator = argumentInfoList
							.argumentsIterator( ); iterator.hasNext( ); i++ )
					{
						Object arg = iterator.next( );
						if ( argIndex == i )
						{
							return ( (IArgumentInfo) arg ).getType( );
						}
					}
				}
				return null;
			}
		}
		return null;
	}
}