(Vista and O2007) When receiving an updated meeting request (times changed),
the reading-pane displays "no action required" at the top of the
request...with no "Accept Decline" buttons. But, if you open the request in
the editor, the buttons show.

The "no action required" shows with an "!" to the left, and if you click on
it, a pop-up is displayed:

"Your calendar has been updated automatically. This meeting request will now
be deleted." [OK or Cancel]

Can anyone shed some light on why this "no action required" shows in the
reading pane? I've tried dillegently to reproduce it on a test system (using
O2007 and O2003) with no luck.

Searching for the phrase or the pop-up message gives no results.

Thanks in advance.