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> I could of course be wrong about what the call back requires - Jamin?
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I think you are hitting the problem where you are trying to do the updates within the call-back.  In the docos, Apple want you to pass the raw events given to you in the call-back to your main event loop.  This is a problem because FB/PG apps dont have a standard main event loop.  INVALRECT
etc generate an event, but the event is stolen by the Nav Dialog, then given back to you in the call-back!  So you must -act- on the update event, not just post another message/event, as it too will be intercepted by the Nav Dialog.  Remember that FB/PG is not running an event-loop while you are in a NavServices call, so no "real" OS events will be handled.  You should be able to use PGs framework to get around this as suggested by Greg's code.

Jamin