(mouse-extend): Handle case where posn-window is a frame.

1 files changed, 4 insertions, 1 deletions

diff --git a/lisp/mouse-sel.el b/lisp/mouse-sel.el
index f079c62f978..861a5ed1759 100644
--- a/lisp/mouse-sel.el
+++ b/lisp/mouse-sel.el
@@ -310,7 +310,10 @@ This should be bound to a down-mouse event."
                  ;; Ignore any movement outside the frame
                  ((eq (car-safe event) 'switch-frame) nil)
                  ((and (posn-window end)
-                       (not (eq (window-frame (posn-window end))
+                       (not (eq (let ((posn-w (posn-window end)))
+                                  (if (windowp posn-w)
+                                      (window-frame posn-w)
+                                    posn-w))
                                 (window-frame orig-window)))) nil)
                      
                  ;; Different window, same frame