WIP Pu disappearing searchbar content

This is an issue related to typeahead, but I found it during browse button fixing. So only the commit ae1d13e is related to this pull request, but for tests it's provided with content of both https://github.com/jirikuncar/invenio/issues/67 and https://github.com/jirikuncar/invenio/pull/130
which need to be merged before.

The detailed description in commit message ae1d13e