>>>Haven't tried, but what about NODEFAULT in InteractiveChange() ?
>>
>>Your NODEFAULT idea works for keyboard input
>>
>>BUT I find that it is unpredictable whether the card swipe will fire interactivechange or keypress, so I still don't know how to test for the following in keypress AND interactivechange :
>>
>>

>>if InputFromSwipe()  <<-- How do I do this
>>  Allow all characters through
>>else
>>  if escape or '1' was pressed
>>    allow through
>>  else
>>    NODEFAULT
>>  endif
>>endif
>>

>
>Yes, I was thinking about it and I think there is no real way to determine what fired the event - swipe or real keyboard input...

Some ideas that have worked for me in the past:

ON KEY LABEL ~ DO FORM whatever WITH 'swipe' TO lxReturnVar && if ~ is the sentinel
ON KEY LABEL &gcMySentinelVariable MyFunction("swipe") && to define the sentenil

For that type of swipe, you can handle it in the ON KEY commands to launch a form with a parameter that tells it where it came from or, if the form is launched already, to set a form prop that states where it came from. Users won't type the beginning sentinel so you can safely assume that it came from the card swipe and not the user. Unless the sentinel char is one that your users regularly type.