Thank you for your post.
A lot depends on what the script is doing at the time. If data is being written to a group of fields (import, replace, etc.), the script step will not be interrupted until the data is finished processing. Pressing command-period will not have any effect during this time.
If you hold down command-period, and assuming Set User Abort is set to On, the script will abort when FileMaker queues up the next script step.
Do you have an example where this does not occur?
Of course the script is processing data otherwise their wouldn't be much point to it, so it's imports, replace etc.
It should be interruptible no matter what, because a bad script running is perhaps even more dangerous than a script interrupted.
But my experience is different than that you describe. When I see the import or replace or import barregraph, it's ok, FMP will allow m to abort it. It's the situation when I only see the Clover + . cursor that I can't really abort reliably.
I think it occurs the most (because most of my script are like that) when an XML import is awaiting the data for the remote server (most of my import are xml through a url which launch a php script that echoes xml, so some time the pho script taes some times) so basicallywhen filemaker is witing the import to start (waiting to get the first data, even though it merely waits, I can't abort). When the imports actually begins then I can Import.
Also prone to the issue are scripts that run the execute applescript commands while awaiting the completion of the applescript script.
And also loops with set fields (that's just a guess because I've much less of those).
But basically my experiences is : if clover cursor only, I can't reliably abort. If progress dialog boxes then I can abort.