protected function buildShow()
    {
        if ($this->show) {
            return;
        }

        $this->show = new FieldDescriptionCollection();
        $mapper = new ShowMapper($this->showBuilder, $this->show, $this);

        $this->configureShowFields($mapper);

        foreach ($this->getExtensions() as $extension) {
            $extension->configureShowFields($mapper);
        }
    }