Hello,
The nodes that are displayed in the Browse dialog are the nodes that the currently logged on user is allowed to view by Security Roles. So, to hide a node from a user in the Browse dialog, you need to hide the appropriate object from a user using Security Roles. However, you should keep in mind that when you hide a directory object from a user with the help of Security Roles, the user will not be able to see the object anywhere in Adaxes: neither in any component of the Web Interface (not only the Browse dialog), nor in the Administration console. For information on how to hide directory object from users, see Hide Active Directory Objects from Users