Collection search doesn't work

Hi ! I tried to follow the instructions carefully, but couldn't make simplsearch work on page searches (global search works well).

Here's my code :

```
---
title: Blog
content:
items: @self.children
limit: 10
order:
by: date
dir: desc
pagination: true
url_taxonomy_filters: true
simplesearch:
route: @self
filters:
- @self
filter_combinator: and
---
...
```

When submitting the form, the query is correctly appended to the url, but the listing page shows all the items, just as if no query was set.
Is it a bug ?