diff -urp openbox-3.5.0.orig/openbox/actions/execute.c openbox-3.5.0/openbox/actions/execute.c
--- openbox-3.5.0.orig/openbox/actions/execute.c	2013-04-25 16:58:14.486361511 +0100
+++ openbox-3.5.0/openbox/actions/execute.c	2013-04-25 17:04:50.354249344 +0100
@@ -130,6 +130,11 @@ static void prompt_cleanup(ObPrompt *p,
     free_func(options);
 }
 
+static void child_watch_cb(GPid pid, gint status, gpointer data)
+{
+    g_spawn_close_pid(pid);
+}
+
 /* Always return FALSE because its not interactive */
 static gboolean run_func(ObActionsData *data, gpointer options)
 {
@@ -238,6 +243,7 @@ static gboolean run_func(ObActionsData *
     else {
         gchar *program = NULL;
         gboolean ok;
+        GPid child_pid;
 
         if (o->sn) {
             program = g_path_get_basename(argv[0]);
@@ -252,10 +258,12 @@ static gboolean run_func(ObActionsData *
         ok = g_spawn_async(NULL, argv, NULL,
                            G_SPAWN_SEARCH_PATH |
                            G_SPAWN_DO_NOT_REAP_CHILD,
-                           NULL, NULL, NULL, &e);
+                           NULL, NULL, &child_pid, &e);
         if (!ok) {
             g_message("%s", e->message);
             g_error_free(e);
+        } else {
+            g_child_watch_add(child_pid, child_watch_cb, NULL);
         }
 
         if (o->sn) {