diff --git a/ptests/ptests.ml b/ptests/ptests.ml
index 259054fa280b6a06e6e51d1fbfd58f59e93d6786..05cb9f5a57aecfc8eeaa3d4d2c3bc4ffb8a6338e 100644
--- a/ptests/ptests.ml
+++ b/ptests/ptests.ml
@@ -711,7 +711,8 @@ let config_options =
            !current_default_cmds
        in
        { current with dc_toplevels = new_top @ current.dc_toplevels;
-                      dc_default_log = !current_default_log });
+                      dc_default_log = !current_default_log @
+                                       current.dc_default_log });
 
     "FILEREG",
     (fun _ s current -> { current with dc_test_regexp = s });