public function isObjDeletable()
    {
        if ($this->isObjDeletable === null) {
            // Overridden by permissions
            if (!$this->checkPermission('delete') || !$this->form()) {
                $this->isObjDeletable = false;
            } else {
                $obj = $this->form()->obj();
                $this->isObjDeletable = !!$obj->id();

                $method = [ $obj, 'isDeletable' ];
                if (is_callable($method)) {
                    $this->isObjDeletable = call_user_func($method);
                }
            }
        }

        return $this->isObjDeletable;
    }