Is there any specific permission needed to make the lucene plugin work?

I did a lot of changes to the default permissions. Now, some time later, I enabled the lucene plugin, but it only works correctly for admin users.

For all other users, the correct number of search results is indicated, but the results themselves are not shown, even though I am searching for stuff that exists in spaces the users have access to.

It's related to the LuceneSearch page. If I use the snipped from the Code/LucenePlugin page, it works.