Do not set mark on single mouse-1 clicks.

* mouse.el (mouse-drag-track): Do not set the mark if the user
releases the mouse without selecting anything.

Fixes: debbugs:11588

2 files changed, 14 insertions, 6 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index a016032e285..845c666bc8b 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2012-06-13  Chong Yidong  <cyd@gnu.org>
+
+        * mouse.el (mouse-drag-track): Do not set the mark if the user
+        releases the mouse without selecting anything (Bug#11588).
+
 2012-06-13  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * textmodes/tex-mode.el (latex-indent): Recognize tex-verbatim at EOB
diff --git a/lisp/mouse.el b/lisp/mouse.el
index f40a0199525..fb2e67408bd 100644
--- a/lisp/mouse.el
+++ b/lisp/mouse.el
@@ -805,7 +805,7 @@ DO-MOUSE-DRAG-REGION-POST-PROCESS should only be used by
          ;; when setting point near the right fringe (but see below).
          (auto-hscroll-mode-saved auto-hscroll-mode)
          (auto-hscroll-mode nil)
-         event end end-point)
+         moved-off-start event end end-point)
 
     (setq mouse-selection-click-count click-count)
     ;; In case the down click is in the middle of some intangible text,
@@ -840,6 +840,9 @@ DO-MOUSE-DRAG-REGION-POST-PROCESS should only be used by
             (redisplay))
           (setq end (event-end event)
                 end-point (posn-point end))
+          ;; Note whether the mouse has left the starting position.
+          (unless (eq end-point start-point)
+            (setq moved-off-start t))
           (if (and (eq (posn-window end) start-window)
                    (integer-or-marker-p end-point))
               (mouse--drag-set-mark-and-point start-point
@@ -880,11 +883,11 @@ DO-MOUSE-DRAG-REGION-POST-PROCESS should only be used by
                    (let (deactivate-mark)
                      (copy-region-as-kill (mark) (point)))))
 
-          ;; If point hasn't moved, run the binding of the
-          ;; terminating up-event.
-          (if do-multi-click
-              (goto-char start-point)
-            (deactivate-mark))
+          ;; Otherwise, run binding of terminating up-event.
+          (cond
+           (do-multi-click (goto-char start-point))
+           (moved-off-start (deactivate-mark))
+           (t (pop-mark)))
           (when (and (functionp fun)
                      (= start-hscroll (window-hscroll start-window))
                      ;; Don't run the up-event handler if the window