I posted this post.
http://www.zkoss.org/forum/listComment/19046

The problem is evenrytime i recall a method which drawing a Grid - not rowRenderer, i tested a minute ago, no problem with rowRenderer -

PageSize of the grid is doubled.

Usually i recall this method after a post is updated, added or deleted ...

I'm not sure it's a bug but pretty sure this issue came up with ZK 6.0.0 upgrade.

Think rows.getChildren().clear() doesn't initialize the pageSize ...

ex)
<grid mold="paging" pageSize="10">

a number of article : 35
it's maxPageSize(end of page) is 4.

refresh after added an article.
it's maxPageSize will be 8.