How to setup autocompletion for database schemas

[mardukbp]

I have a database in BaseX named books. I get the root node with

let $books := db:open('books')

In Settings I set the Database installation path to C:\Program Files (x86)\BaseX. And the checkbox "Register database schemas for autocompletion" is set.

However, when I write a query like

for $book in $books/catalog/book

I get no autocompletion. I tried changing the database installation path to C:\Program Files (x86)\BaseX\data\books to no avail.

What am I missing or doing wrong?