diff --git a/emacs-lisp/windows_and_frames.org b/emacs-lisp/windows_and_frames.org
index ba88827..863aa78 100644
--- a/emacs-lisp/windows_and_frames.org
+++ b/emacs-lisp/windows_and_frames.org
@@ -13,19 +13,19 @@ Disable window changing using the mouse, it saves me from accidental switches.
 
 #+begin_src emacs-lisp
   (defun cv/mouse-set-point (fun event &optional promote)
-    (let ((window (car (car (cdr event)))))
+    (let ((window (posn-window (event-start event))))
       (when (equal window (selected-window))
         (funcall fun event promote))))
   (advice-add 'mouse-set-point :around 'cv/mouse-set-point)
 
   (defun cv/mouse-drag-region (fun event)
-     (let ((window (car (car (cdr event)))))
-       (when (equal window (selected-window))
+     (let ((window-end (posn-window (event-end event))))
+       (when (equal window-end (selected-window))
         (funcall fun event))))
   (advice-add 'mouse-drag-region :around 'cv/mouse-drag-region)
 
   (defun cv/mouse-set-region (fun event)
-     (let ((window (car (car (cdr event)))))
+     (let ((window (posn-window (event-start event))))
        (when (equal window (selected-window))
         (funcall fun event))))
   (advice-add 'mouse-set-region :around 'cv/mouse-set-region)