smart group contacts list: contact selections aren't remembered

to reproduce:

• view contacts for a smart group. example here: http://drupal.demo.civicrm.org/civicrm/group/search?reset=1&force=1&context=smog&gid=8
• select a few records from the first page
• click next to view records on the second page, and select a few
• from the action dropdown, choose to export
• result: popup indicating you need to choose some records

there were a few times when it did seem to remember the selections from the multiple pages, but for the most part, it fails.