The text states "Search pages...".
Actually, you can't search for pages.
You can either paste the link to one, or select the recently accessed pages from the dropdown. Even if you type the name of a page that you have not accessed recently, it on't be retrieved.
- Click on the link button dropdown -> Link Confluence page.
The field will state that you can select recently accessed pages, or paste the link to a specific one.
The text states that you can search for pages, giving the idea that users can search for any page by just typing in their name.
None at the moment.