(mouse-drag-region): Be smart about which end

gets point and which end gets the mark.

1 files changed, 16 insertions, 3 deletions

diff --git a/lisp/mouse.el b/lisp/mouse.el
index bd4e439b21e..41fda55689b 100644
--- a/lisp/mouse.el
+++ b/lisp/mouse.el
@@ -574,9 +574,22 @@ remains active.  Otherwise, it remains until the next input event."
                         (cons event unread-command-events)))
               (if (not (= (overlay-start mouse-drag-overlay)
                           (overlay-end mouse-drag-overlay)))
-                  (let (last-command this-command)
-                    (push-mark (overlay-start mouse-drag-overlay) t t)
-                    (goto-char (overlay-end mouse-drag-overlay))
+                  (let* ((stop-point (posn-point (event-end event)))
+                         ;; The end that comes from where we ended the drag.
+                         ;; Point goes here.
+                         (region-termination
+                          (if (< stop-point start-point)
+                              (overlay-start mouse-drag-overlay)
+                            (overlay-end mouse-drag-overlay)))
+                         ;; The end that comes from where we started the drag.
+                         ;; Mark goes there.
+                         (region-commencement
+                          (- (+ (overlay-end mouse-drag-overlay)
+                                (overlay-start mouse-drag-overlay))
+                             region-termination))
+                         last-command this-command)
+                    (push-mark region-commencement t t)
+                    (goto-char region-termination)
                     (copy-region-as-kill (point) (mark t))
                     (mouse-show-mark)
                     (mouse-set-region-1))