--- src/w32fns.c	2018-04-23 23:18:03.000000000 +0900
+++ src/w32fns.c	2018-06-04 23:52:06.680805500 +0900
@@ -4544,6 +4544,7 @@ w32_wnd_proc (HWND hwnd, UINT msg, WPARA
 
 	  set_ime_composition_window_fn (context, &form);
 	  release_ime_context_fn (hwnd, context);
+	  goto dflt;
 	}
       /* We should "goto dflt" here to pass WM_IME_STARTCOMPOSITION to
 	 DefWindowProc, so that the composition window will actually