diff -pruN mozc-2.28.4950.102.orig/unix/emacs/mozc.el mozc-2.28.4950.102/unix/emacs/mozc.el
--- mozc-2.28.4950.102.orig/unix/emacs/mozc.el 2022-12-20 14:42:26.000000000 +0900
+++ mozc-2.28.4950.102/unix/emacs/mozc.el 2023-01-11 15:26:30.380067572 +0900
@@ -661,7 +661,7 @@ This hack could be moved to mozc-posn-at
"Return the width of WINDOW in pixel.
WINDOW defaults to the selected window."
(let ((rect (window-inside-pixel-edges window)))
- (- (third rect) (first rect))))
+ (- (cl-third rect) (cl-first rect))))
(defun mozc-header-line-height ()
"Return the height of the header line.