Optimized User Search
Confluence Only
There are two options below the “Directory” selector, both intended to improve user-search performance. These options also apply to the user search in the "Share this page" modal, the page restriction modal and to the user search on the Global Permissions settings page.
Use Optimized User Search
This option is only available if you didn’t select a directory in (1) or if you selected “Any” as a value, which is equal. It only approves search performance when the users being optimized are sourced in multiple directories.

Only search for users in the selected directory
If all the users being optimised are in the same directory and you’ve selected that, with this option enabled, users will only be searched in this directory.
