What do I need to do to be able to apply HCI overlays or use the overlay tool?
The client’s jas.ini file needs to be edited:
^In section labeled:  ^'[JAS HCI System]'^
|Add line:            |OverlaysAllowed=true|
|Comments:            |This section header should already exist|


This is allows you to __view or edit__ overlays.  This file is located on the individual’s computer where the packaged or open image resides.  It enables the Scenario Browser’s menu Tools >> Method Source Overlay tool.  If that entry is absent, overlays can only be entered/edited in Data View. 

Note:  If you can view the overlay tool, that doesn’t necessarily mean that your site allows those overlays to run.  Vice versa, even if you can’t use the overlay tool, but you have overlays in your scenario, the overlays will still be applied if the server allows them.