Applied patch attached to issue2550723. Problem in index page @pagesize=0 not properly propigated to previous batch link (is set to actual number of entries displayed). Using demo.py verified original issue with 0 page size. Also verified that a non-zero page size was properly propigated (values 5 and 20). Applied patch attached to issue. Verified issue with size 0 fixed. Verified that values 5 and 20 worked correctly. Updated CHANGES.txt.

The existence of this file enables the Zope product refresh option.
Read the Zope documentation for more info about product refresh.