Symphony.

I have a Select Box Link field for a Categories section to categories entries in a Journal section. The select box link field in the Journal section is set to “Allow selection of multiple options”. I have created a data source (Journal by Categories) for the Journal section that has the XML output options configured to group by Categories. When I attach the data source to a page and view the page on the front end, I receive the following error:

Illegal offset type in isset or empty
/Users/stephen/Sites/bauhouse-207/extensions/selectbox_link_field/fields/field.selectbox_link.php line 244

239     
240     
241     public function findFieldIDFromRelationID($id){
242         if(is_null($id)) return NULL;
243         
244         if (isset(self::$cacheRelations[$id])) {
245             return self::$cacheRelations[$id];
246         }
247
248         try{

When I change the configuration for the Categories select box field in the Journal section by unchecking the checkbox “Allow selection of multiple options”, the error is returned on the front end page. When any entries that have been saved with multiple categories are resaved with a single category selected, the front end page displays without the error.

So, my question is: Is it possible to group by multiple categories? If so, this is a bug. If not, the option to group by multiple categories should not be available.