protected function getFormActionFromRequest(HTTPRequest $r)
    {
        $action = $r->requestVar('action');
        $formAction = $this->record->findActionByName($action);

        if (!$formAction instanceof BetterButtonNestedForm) {
            throw new Exception("Action $action doesn't exist or is not a BetterButtonNestedForm");
        }

        return $formAction;
    }