Rev app 'not responding' under Vista, but fine in XP

[Martin Blackman]

Hi folks

Microsoft Vista is classifying my Rev application as 'Not responding'
when it runs a particularly intensive handler. The title bar changes
and screen updates cease. But the program is still working just fine
underneath all that, and once the handler finishes Vista releases the
stranglehold and updates the window.  However users may be
understandably concerned and will not see the progress bar update
normally shown by the program.
This does not happen on XP, it seems that Vista is a little overzealous here.
I believe Rev does its garbage collection after a handler finishes. So
a big repeat loop could instead be changed to repeated calls to a sub
handler.
But I think this would add overhead and besides I'm struggling to
think of a way to modify a couple of my problematic handlers in this
fashion.  Has anyone here had any successful dealings with this issue?

regards
Martin Blackman