Bug 136270 Group's data binding column can only be used by the group itself
If you add some data binding columns to a group, these columns can only be used by this group itself. It should has a way to make the child can use the parent group's data binding column.
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/util/DEUtil.java
Map argMap = new LinkedHashMap( methods.size( ) * 2 );
		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++ )
					{
						IArgumentInfo arg = (IArgumentInfo) iterator.next( );
						argMap.put( arg.getName( ), arg.getType( ) );
					}
				}
			}
		}
		return argMap;
	}
	/**
	 * @deprecated
	 */
	public static List getDataSources( )
	{