diff --git a/gramps/plugins/drawreport/ancestortree.py b/gramps/plugins/drawreport/ancestortree.py
index 35f9b0065..46bd3ac22 100644
--- a/gramps/plugins/drawreport/ancestortree.py
+++ b/gramps/plugins/drawreport/ancestortree.py
@@ -231,8 +231,9 @@ class MakeAncestorTree(AscendPerson):
         myself.text = self.calc_items.calc_person(index,
                                                   indi_handle, fams_handle)
 
-        myself.add_mark(self.database,
-                        self.database.get_person_from_handle(indi_handle))
+        if indi_handle is not None: # None is legal for an empty box
+            myself.add_mark(self.database,
+                            self.database.get_person_from_handle(indi_handle))
 
         self.canvas.add_box(myself)