Do you have a ton of users and need to be able to browse through them in our designers but have had issues?
By default we will only return 100 users from Active Directory. However there is an option to change this. To do so you must Change the default settings for the User Roles Manager Service under SmartObjects > Services > User Role Manager Service under Management Console in Workspace.
The piece you want to change is show below, it is called FindUsersDefault and is set to groupname=null;size=100. You can change the size = number

Now you can set this number to whatever size you want and or works best. But this setting exists to keep performance of the object browser in mind. I would recommended that rather than setting this to a big number that will end up pulling back more users, that you instead use the search feature to locate a specific user.
So now if you are ever using the object browser and are seeing this behaviour now you know both why, and what to do.