diff --git a/openbox/config.c b/openbox/config.c
index c58033bb..c86b739c 100644
--- a/openbox/config.c
+++ b/openbox/config.c
@@ -388,7 +388,7 @@ typedef struct
 {
     const gchar *button;
     const gchar *context;
-    ObMouseAction mact;
+    const ObMouseAction mact;
     const gchar *actname;
 } ObDefMouseBind;