The BOUNDED (abbreviated BO) option will cause the search to be bounded
 by a page delimiter.  By default, the search is unbounded, which means
 that the entire buffer will be searched.  This option has effect only in
 change mode.

 The UNBOUNDED (abbreviated U) option causes the search not to be bounded
 by a page delimiter, which means that the entire buffer will be
 searched.  This is the default.  This option has effect only in change
 mode.