Menu not active

Example, I has routers list:

```
- admin.article
- admin.article.list
- admin.article.view
```

And my menus list:

```
$menu->dropdown(trans('Article'), function ($sub) {
    $sub->route('admin.article.list', trans('List'), [], 1, []);
}, 2, []);

```

When i vitsited to router:`admin.article.view`, menu `Article` do not add class "active".
