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
{
		if ( obj instanceof Class )
		{
			obj = ( (Class) obj ).getName( );
		}
		return obj.toString( )
				.substring( obj.toString( ).lastIndexOf( "." ) + 1 ); 
	}
	/**
	 * Gets the definition for the element with the specified name
	 * 
	 * @param elementName
	 *            the name of the element
	 * 
	 * @return Returns the definition, or null if the element is not defined.
	 */
	public static IElementDefn getElementDefn( String elementName )
	{
		IElementDefn defn = DesignEngine.getMetaDataDictionary( )
				.getElement( elementName );
		if ( defn == null )
		{
			defn = DesignEngine.getMetaDataDictionary( )
					.getExtension( elementName );
		}
		return defn;
	}
	/**
	 * Get display label of report element
	 *