emacs-27 d7c2233: Fix cursor-sensor--detect when current buf != selected window's buf

[Eli Zaretskii]

branch: emacs-27
commit d7c22338d2d461e0b55a6628fed1917c08715292
Author: Federico Tedin <address@hidden>
Commit: Eli Zaretskii <address@hidden>

    Fix cursor-sensor--detect when current buf != selected window's buf
    
    * lisp/emacs-lisp/cursor-sensor.el (cursor-sensor--detect): Avoid
    trying to read text properties from position taken from another
    buffer.  (Bug#38740)
---
 lisp/emacs-lisp/cursor-sensor.el | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/lisp/emacs-lisp/cursor-sensor.el b/lisp/emacs-lisp/cursor-sensor.el
index d8e8eeb..7728e78 100644
--- a/lisp/emacs-lisp/cursor-sensor.el
+++ b/lisp/emacs-lisp/cursor-sensor.el
@@ -146,9 +146,10 @@ By convention, this is a list of symbols where each symbol 
stands for the
            ;; It's often desirable to make the cursor-sensor-functions property
            ;; non-sticky on both ends, but that means get-pos-property might
            ;; never see it.
-           (new (or (get-char-property point 'cursor-sensor-functions)
-                    (unless (<= (point-min) point)
-                      (get-char-property (1- point) 
'cursor-sensor-functions))))
+           (new (and (eq (current-buffer) (window-buffer))
+                     (or (get-char-property point 'cursor-sensor-functions)
+                         (unless (<= (point-min) point)
+                           (get-char-property (1- point) 
'cursor-sensor-functions)))))
            (old (window-parameter window 'cursor-sensor--last-state))
            (oldposmark (car old))
            (oldpos (or (if oldposmark (marker-position oldposmark))