We already were setting the proper `Cache-Control` headers for the datagrid listview, which is used for inline reloading of the datagrid contents. Unfortunately, we didn't have matching headers for the datagrid pages themselves. This was mostly not noticeable, except for one highly annoying thing: if you selected a checkbox and then clicked an action (such as archive), the action would run and everything would look fine. If the page was then reloaded, Firefox would very helpfully try to re-select checkbox in the same row number, even though that didn't correspond to the one that was checked and archived. Setting the cache headers (in particular, `Cache-Control: no-store`) turns off this behavior in Firefox. While I was doing this I replaced the existing code with Django's `add_never_cache_headers`, which does the same thing with less verbosity. Testing Done: - Ran unit tests. - Selected a review request and clicked "Archive" in the actions sidebar. Saw the datagrid update as expected. Clicked the reload button in the browser, and saw that Firefox no longer tried to select any checkboxes.