I just checked out the project pagingsortingwithclientsideselecting-ajax.zip from this Code Library
referenced from this page
and found a strange behaviour: the 'select all' checkbox gets selected when returning to page 2.
Steps to reproduce the issue:
1) Start the project
2) Select row 1 on page 1
3) Select row 2 on page 2
4) Navigate to page 1 and back to page 2
5) The 'select all' checkbox is selected!!!
Can someone confirm this? Or even better: is there a workaround for this?