diff --git a/source/main.pas b/source/main.pas
index d22e276d..70c8c1b6 100644
--- a/source/main.pas
+++ b/source/main.pas
@@ -9401,8 +9401,12 @@ begin
       Allowed := Results.SaveModifications;
       DisplayRowCountStats(Sender);
     end else if Results.Inserted then begin
-      Results.DiscardModifications;
-      Sender.DeleteNode(OldNode);
+      if NewNode <> nil then begin
+        Results.DiscardModifications;
+        Sender.DeleteNode(OldNode);
+      end else begin
+        Allowed := False;
+      end;
     end;
   end;
 end;