1 files changed, 7 insertions, 4 deletions

diff --git a/lisp/mouse.el b/lisp/mouse.el
index 41b543e3892..07b525546cf 100644
--- a/lisp/mouse.el
+++ b/lisp/mouse.el
@@ -759,12 +759,14 @@ If DIR is positive skip forward; if negative, skip backward."
                                   (throw 'mouse-show-mark t)))))
           (move-overlay mouse-drag-overlay (point) (mark t))
           (catch 'mouse-show-mark
-            ;; In this loop, read and execute scroll bar events.
-            ;; Otherwise, if we 
+            ;; In this loop, execute scroll bar and switch-frame events.
+            ;; Also ignore down-events that are undefined.
             (while (progn (setq event (read-event))
                           (setq events (append events (list event)))
                           (setq key (apply 'vector events))
                           (or (and (consp event)
+                                   (eq (car event) 'switch-frame))
+                              (and (consp event)
                                    (eq (posn-point (event-end event))
                                        'vertical-scroll-bar))
                               (and (memq 'down (event-modifiers event))
@@ -772,8 +774,9 @@ If DIR is positive skip forward; if negative, skip backward."
                                    (not (mouse-undouble-last-event events))
                                    (not (member key mouse-region-delete-keys)))))
               (and (consp event)
-                   (eq (posn-point (event-end event))
-                       'vertical-scroll-bar)
+                   (or (eq (car event) 'switch-frame)
+                       (eq (posn-point (event-end event))
+                           'vertical-scroll-bar))
                    (let ((keys (vector 'vertical-scroll-bar event)))
                      (and (key-binding keys)
                           (progn