A patch from Sascha Rodekamp "Entity ProdCatalogCategoryType Parent Relation" (https://issues.apache.org/jira/browse/OFBIZ-3793) - OFBIZ-3793 The ProdCatalogCategoryType didn't have a parent Relation. Here is a fix that added a parentTypeId field and the relation definition
ofbiz/trunk/applications/product/entitydef/entitymodel.xml