[damianharvey]

As it says in the seam reference:

The <param> declaration is bidirectional

[dkane]

Ok, it works in the way you recommend. Thanks.

The last question :
for ajax request, we can write

<a:actionParam value="#{row.id}" assignTo="#{testBean.id}">

- no need to specify "param" tag in pages.xml - right ?

There is no assignTo in f:param, though..

[pmuir]

Yes, but this doesn't give you parameter propagation of course.