Properly determine which fields to show

core/views/ui/drilldown.py

@@ -178,14 +178,7 @@ class DrilldownTableView(SingleTableView):
     def get(self, request, *args, **kwargs):
         self.object_list = self.get_queryset(request)
         show = []
-        if len(self.object_list) > 0:
-            first = self.object_list[0]
-            fields = first.keys()
-            for field in fields:
-                # values_present = all([x[field] is not None for x in self.object_list])
-                # if values_present:
-                if field not in show:
-                    show.append(field)
+        show = set().union(*(d.keys() for d in self.object_list))
         allow_empty = self.get_allow_empty()
 
         if not allow_empty: