--- gtkimcontextsimple.c.ORIGINAL	2008-09-30 19:33:20.000000000 +0100
+++ gtkimcontextsimple.c	2008-10-01 11:43:28.000000000 +0100
@@ -407,11 +407,19 @@
   return FALSE;
 }
 
-/* When updating the table of the compose sequences, also update here.
+/* Checks if a keysym is a dead key. Dead key keysym values are defined in
+ * ../gdk/gdkkeysyms.h and the first is GDK_dead_grave. As X.Org is updated,
+ * more dead keys are added and we need to update the upper limit.
+ * Also checks if the keysym belongs to the non-spacing mark Unicode category,
+ * by invoking gdk_keyval_to_unicode(). For keysyms like 0x1000000 + 0x0301,
+ * it converts them to 0x301, which makes g_unichar_type() report them as
+ * non-spacing mark. Thus, we check that the value is less then 0x1000000.
+ * check_algorithmically() does not handle keysyms > 0x1000000.
  */
 #define IS_DEAD_KEY(k) \
     (((k) >= GDK_dead_grave && (k) <= (GDK_dead_dasia+1)) || \
-     g_unichar_type (gdk_keyval_to_unicode (k)) == G_UNICODE_NON_SPACING_MARK)
+     ((g_unichar_type (gdk_keyval_to_unicode (k)) == G_UNICODE_NON_SPACING_MARK) && \
+      ((k) < 0x1000000)))
 
 static gboolean
 check_algorithmically (GtkIMContextSimple    *context_simple,
