I have a form that contains a list of items generated dynamically. The form normally contains includes two listboxes that provide selections of items with which to filter the list. (More specifically, the list of items are jobs that include the employer and whethe the jobs have been viewed or not by the visitor. One list is a list of all employes having their jobs displayed, the other allows filtering of the list based on whether the jobs have been viewed or not. Selecting an employer, for example, will trigger a callback to filter the list to show just jobs from that employer.)

The form works fine under these circumstances. However, when the website visitor is not a registered job seeker, the backend code doesn't know if the visitor has viewed jobs or not, so the listbox to filter the list by viewed status is made 'not visible' The first time the page is viewed selecting an employer from the listbox of employes no longer triggers a callback, but if the page is displayed a second time ( for example, after viewing a job then returning to the list of available jobs) selecting an employe will trigger a callback.

Suggestions?