bug#13643: About symbolic prefix

[Xue Fuqiao]

In (info "(elisp) Active Keymaps"):

   When the key sequence starts with a mouse event (optionally preceded
by a symbolic prefix), the active keymaps are determined based on the
position in that event.

I don't know what the "symbolic prefix" means here (maybe it means
something like `down-mouse-1'), but I think it doesn't mean the
`gnus-symbolic-argument' in Gnus.  It is confusing here.

-- 
Best regards, Xue Fuqiao.
http://www.emacswiki.org/emacs/XueFuqiao