an equivalent to "on reopen" ?

when writing an applet or a droplet in script editor, and saving it as “stay open”, it is possible to use an “on reopen” handler, which gets called, as far as i understand, only when a user is explicitly sending a run (or launch) command to the application,(i.e. double-clicking its icon in the finder, clicking its dock icon, etc.) while it is already running.
i’m trying to achieve the same result with ASS, but as far as i can tell, the available handlers for the “file owner” object behave differently:

“will finish launching” and “launched” handlers : will only be called when the application launches, while it wasn’t running.

while

“will become active” and “activated” do get called when the application is “reactivated” which may be when it is “reopened” but also when it becomes activated by clicking on one of its windows, hiding another application, Cmd-Tab switching, etc. which may not be so useful in some situation.

does anybody know a way to imitate the “reopen” behavior?

thanks.