diff --git a/libs/gtkmm2ext/bindings.cc b/libs/gtkmm2ext/bindings.cc
index 155b2cf11c..d06a3a28c1 100644
--- a/libs/gtkmm2ext/bindings.cc
+++ b/libs/gtkmm2ext/bindings.cc
@@ -527,7 +527,7 @@ Bindings::replace (KeyboardKey kb, Operation op, string const & action_name, boo
 bool
 Bindings::add (KeyboardKey kb, Operation op, string const& action_name, bool can_save)
 {
-	if (is_registered(op, action_name)) {
+	if (is_registered (op, action_name)) {
 		return false;
 	}