Hello,
When the Tree View is used to select the target OU, the all parent OUs must also match the search criteria. The Tree View is used if the user has the permission to view the domain object.
In the next release of Adaxes we are planning to introduce an option for Home Page actions that will control which view to use to select the target OU (Tree View or List View). The next version is scheduled for the end of January 2012.
BTW, the LDAP filter on the screenshot is different from the LDAP filter you specified
(&(objectClass=organizationalUnit)(name=Users*)).