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
*/
	public static GroupElementHandle getGroupElementHandle( List modelList )
	{
		if ( SessionHandleAdapter.getInstance( ).getReportDesignHandle( ) == null )
		{
			return GroupElementFactory.newGroupElement( SessionHandleAdapter.getInstance( )
					.getReportDesignHandle( ),
					Collections.EMPTY_LIST );
		}
		return GroupElementFactory.newGroupElement( SessionHandleAdapter.getInstance( )
				.getReportDesignHandle( ),
				modelList );
	}
	/**
	 * Checks if the library is included.
	 * 
	 * @param handle
	 * @return
	 */
	public static boolean isIncluded( LibraryHandle handle )
	{
		return handle.getNamespace( ) != null;
	}
	public static List getClasses( )
	{
		return getClasses( new AlphabeticallyComparator( ) );
	}
	public static List getClasses( Comparator comp )
	{
		List classes = DesignEngine.getMetaDataDictionary( ).getClasses( );