Nedit has a nice feature: It notices external changes
to an opened file, i.e. when an external program
modifies the file. When you enter the editor window
again, after the file was modified by another program,
the editor asks you if you want to reload the file. It
even warns you that you will loose your unsaved
changes, if you have any.

This feature is nice since it makes it possible to
cooperatively edit one file on a network-server. You
can also let some shell-scripts modify your text file
and go on editing afterwards, without the need to
manually reload the file. More important than this
comfort is that you can not just forget to reload
(which could kill quite some work).

It would be very nice to have this feature in gedit.

Hint: This request has a duplicate in 
http://sourceforge.net/tracker/index.php?func=detail&aid=1064441&group_id=7&atid=350007