Index: ../trunk-jpl/src/c/datastructures/DataSet.cpp
===================================================================
--- ../trunk-jpl/src/c/datastructures/DataSet.cpp	(revision 23547)
+++ ../trunk-jpl/src/c/datastructures/DataSet.cpp	(revision 23548)
@@ -437,6 +437,11 @@
 		for(int i=0;i<objects.size();i++){
 			id_offsets[i]=i;
 			sorted_ids[i]=objects[i]->Id();
+
+			/*In debugging mode, make sure Ids are ACTUALLY sorted...*/
+			#ifdef _ISSM_DEBUG_
+			if(i>0) _assert_(sorted_ids[i]>sorted_ids[i-1]);
+			#endif
 		}
 	}