diff --git a/src/bin/e_client.h b/src/bin/e_client.h
index 3745f6466..0084b596a 100644
--- a/src/bin/e_client.h
+++ b/src/bin/e_client.h
@@ -338,7 +338,7 @@ struct E_Client
       double                    min_aspect, max_aspect;
       Ecore_Window            icon_window;
       Ecore_Window            window_group;
-      Ecore_Window            transient_for;
+      uint64_t                transient_for;
       Ecore_Window            client_leader;
 #ifndef HAVE_WAYLAND_ONLY
       Ecore_X_Window_State_Hint initial_state;