The problem described is fixed by a patch to Adobe Type Manager. This patch is available from Adobe Tech Support. Their phone number is 408-986-6500. Customers should call this number, describe the problem (mirroring monitor off of PowerBook 500 does not show characters being drawn with aid of ATM), and ask for the patch. Apparently, Adobe does not have a name for this patch, and I was unable to get any other reference from them.
This patch is free to registered users of Adobe Type Manager (the tech support line will ask for serial number of diskette).
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