don't think you'll reset the browse on tab selection (*) - but rather set it on the field, on the first tab, that sets the session value in the first place.
ie say you have a date field on tab 1, then reset the browse when the date changes.
(*) You don't want to do it on tab if you can help it, because there are many different tab "styles" - including ones where all the tabs are visible all the time, so you want o make it work in "all cases" as much as possible.
cheers
Bruce