Backport mouse.el fix (r108702/108703) from trunk
authorChong Yidong <cyd@gnu.org>
Tue, 7 Aug 2012 03:26:09 +0000 (11:26 +0800)
committerChong Yidong <cyd@gnu.org>
Tue, 7 Aug 2012 03:26:09 +0000 (11:26 +0800)

Trivial merge