'Handle the page change in the page control.'

def page_change(self, page):

    if self.req_res_ids:
        request_id = self.req_res_ids[page]
        try:
            historyItem = self._historyItem.read(request_id)
        except:
            self.rrV.request.clear_panes()
            self.rrV.response.clear_panes()
            self.rrV.set_sensitive(False)
            self.title0.set_markup('<b>Error</b>')
        else:
            self.title0.set_markup(('<b>Id:    %d</b>' % request_id))
            self.rrV.request.show_object(historyItem.request)
            self.rrV.response.show_object(historyItem.response)
            self.rrV.set_sensitive(True)
