diff --git a/gramps/gui/views/treemodels/flatbasemodel.py b/gramps/gui/views/treemodels/flatbasemodel.py
index 6b138e82d..9f8793d04 100644
--- a/gramps/gui/views/treemodels/flatbasemodel.py
+++ b/gramps/gui/views/treemodels/flatbasemodel.py
@@ -398,9 +398,14 @@ class FlatNodeMap(object):
         insert_pos = bisect.bisect_left(self._index2hndl, srtkey_hndl)
         self._index2hndl.insert(insert_pos, srtkey_hndl)
         #make sure the index map is updated
-        for hndl, index in self._hndl2index.items():
-            if index >= insert_pos:
-                self._hndl2index[hndl] += 1
+        if sys.version_info[0] < 3: # keep this, for speed in Python2
+            for hndl, index in self._hndl2index.iteritems(): # in Python2 "if"
+                if index >= insert_pos:
+                    self._hndl2index[hndl] += 1
+        else:
+            for hndl, index in self._hndl2index.items():
+                if index >= insert_pos:
+                    self._hndl2index[hndl] += 1
         self._hndl2index[srtkey_hndl[1]] = insert_pos
         #update self.__corr so it remains correct
         if self._reverse:
@@ -442,9 +447,14 @@ class FlatNodeMap(object):
         if self._reverse:
             self.__corr = (len(self._index2hndl) - 1, -1)
         #update the handle2path map so it remains correct
-        for key, val in self._hndl2index.items():
-            if val > index:
-                self._hndl2index[key] -= 1
+        if sys.version_info[0] < 3: # keep this, for speed in Python2
+            for key, val in self._hndl2index.iteritems(): # in Python2 "if"
+                if val > index:
+                    self._hndl2index[key] -= 1
+        else:
+            for key, val in self._hndl2index.items():
+                if val > index:
+                    self._hndl2index[key] -= 1
         return Gtk.TreePath((delpath,))
 
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