* mouse.el (mouse-drag-region): Correctly handle drags which enter

	other frames.

diff --git a/lisp/mouse.el b/lisp/mouse.el
index 100860f..592d2b7 100644 (file)
--- a/lisp/mouse.el
+++ b/lisp/mouse.el
@@ -161,6 +161,7 @@ This must be bound to a button-down mouse event."
   (let* ((start-posn (event-start start-event))
         (start-point (posn-point start-posn))
         (start-window (posn-window start-posn))
+        (start-frame (window-frame start-window))
         (bounds (window-edges start-window))
         (top (nth 1 bounds))
         (bottom (if (window-minibuffer-p start-window)
@@ -176,30 +177,45 @@ This must be bound to a button-down mouse event."
     (let (event end end-point)
       (track-mouse
        (while (progn
-                (setq event (read-event)
-                      end (event-end event)
-                      end-point (posn-point end))
-                (mouse-movement-p event))
-         ;; Is the mouse anywhere reasonable on the frame?
-         (if (windowp (posn-window end))
-             ;; If the mouse is outside the current window, scroll it.
-             (if (or (not (eq (posn-window end) start-window))
-                     (not (integer-or-marker-p end-point)))
-                 ;; Which direction should we scroll the window?
-                 (let ((mouse-row
-                        (+ (nth 1 (window-edges (posn-window end)))
-                           (cdr (posn-col-row end)))))
-                   (cond
-                    ((< mouse-row top)
-                     (mouse-scroll-subr
-                      (- mouse-row top) mouse-drag-overlay start-point))
-                    ((and (not (eobp))
-                          (>= mouse-row bottom))
-                     (mouse-scroll-subr (1+ (- mouse-row bottom))
-                                        mouse-drag-overlay start-point))))
-               (goto-char end-point)
-               (move-overlay mouse-drag-overlay
-                             start-point (point))))))
+                (setq event (read-event))
+                (or (mouse-movement-p event)
+                    (eq (car-safe event) 'switch-frame)))
+
+         (if (eq (car-safe event) 'switch-frame)
+             nil
+           (setq end (event-end event)
+                 end-point (posn-point end))
+
+           (cond
+
+            ;; Ignore switch-frame events.
+            ((eq (car-safe event) 'switch-frame))
+
+            ;; Are we moving within the original window?
+            ((and (eq (posn-window end) start-window)
+                  (integer-or-marker-p end-point))
+             (goto-char end-point)
+             (move-overlay mouse-drag-overlay
+                           start-point (point)))
+
+            ;; Are we moving on a different window on the same frame?
+            ((and (windowp (posn-window end))
+                  (eq (window-frame (posn-window end)) start-frame))
+             (let ((mouse-row
+                    (+ (nth 1 (window-edges (posn-window end)))
+                       (cdr (posn-col-row end)))))
+               (cond
+                ((< mouse-row top)
+                 (mouse-scroll-subr
+                  (- mouse-row top) mouse-drag-overlay start-point))
+                ((and (not (eobp))
+                      (>= mouse-row bottom))
+                 (mouse-scroll-subr (1+ (- mouse-row bottom))
+                                    mouse-drag-overlay start-point)))))
+
+            ;; Otherwise, we have no idea where the mouse is.
+            (t)))))
+
       (if (and (eq (get (event-basic-type event) 'event-kind) 'mouse-click)
               (eq (posn-window (event-end event)) start-window)
               (numberp (posn-point (event-end event))))