followcursor-mode

To use, first add to your config:

    (require 'followcursor-mode

Then prepare two windows with different buffers, enable the mode
in one of them with:

    (followcursor-mode)

You  will  be   asked  for  a  `thing-at-point'  to   be  used  for
highlighting,  the  default  being  `lazyword',  which  is  a  mode
indepenent  thing matching  words including  some punctuation.  You
may, however, use any other symbol from the list.

Move around in that buffer as you wish. Whenever `point' is on a
match, it will be highlighted in both buffers.