diff --git a/glib/gmain.c b/glib/gmain.c
index 9c5f0ef1e..15581ee7a 100644
--- a/glib/gmain.c
+++ b/glib/gmain.c
@@ -3125,10 +3125,10 @@ g_main_current_source (void)
  * {
  *   SomeWidget *self = data;
  *    
- *   GDK_THREADS_ENTER ();
+ *   g_mutex_lock (&self->idle_id_mutex);
  *   // do stuff with self
  *   self->idle_id = 0;
- *   GDK_THREADS_LEAVE ();
+ *   g_mutex_unlock (&self->idle_id_mutex);
  *    
  *   return G_SOURCE_REMOVE;
  * }
@@ -3136,9 +3136,19 @@ g_main_current_source (void)
  * static void 
  * some_widget_do_stuff_later (SomeWidget *self)
  * {
+ *   g_mutex_lock (&self->idle_id_mutex);
  *   self->idle_id = g_idle_add (idle_callback, self);
+ *   g_mutex_unlock (&self->idle_id_mutex);
  * }
  *  
+ * static void
+ * some_widget_init (SomeWidget *self)
+ * {
+ *   g_mutex_init (&self->idle_id_mutex);
+ *
+ *   // ...
+ * }
+ *
  * static void 
  * some_widget_finalize (GObject *object)
  * {
@@ -3147,6 +3157,8 @@ g_main_current_source (void)
  *   if (self->idle_id)
  *     g_source_remove (self->idle_id);
  *    
+ *   g_mutex_clear (&self->idle_id_mutex);
+ *
  *   G_OBJECT_CLASS (parent_class)->finalize (object);
  * }
  * ]|
@@ -3163,12 +3175,12 @@ g_main_current_source (void)
  * {
  *   SomeWidget *self = data;
  *   
- *   GDK_THREADS_ENTER ();
+ *   g_mutex_lock (&self->idle_id_mutex);
  *   if (!g_source_is_destroyed (g_main_current_source ()))
  *     {
  *       // do stuff with self
  *     }
- *   GDK_THREADS_LEAVE ();
+ *   g_mutex_unlock (&self->idle_id_mutex);
  *   
  *   return FALSE;
  * }