Recognizing URL's in Mutt

["Michael W. Cole" <colemw@verizon.net>]

I am using mutt with vim as the editor.  I have seen in the past where
the url's on a line in xterm will be underlined when the mouse moves
over it.  You could then double click the mouse and the web browser
would open that url.  How, what, where can I look, do, read to
understand how to implement this behavior in mutt, vim, xterm etc.
BTW, my xterm is not performing this behavior now.  
Michael

-- 
Michael Ward Cole, DO
936 Josephine Crescent
Virginia Beach, Virginia 23464
757 420-3804 (Home)
757 475-3184 (Pager)