"Max" wrote:

Did you re-confirm* the formula after ensuring the format was ok ?
*eg: click inside the formula bar, press ENTER

In fact, I'm not sure...

..the cell formatted as text would (normally) show only the result
of the particular calculation formatted as text; not the entire formula.

I'm not sure about that. Think cells which are pre-formatted as text would
exhibit behaviour very similar to what you posted (Just tried it here <g)

That's true. But it doesn't really solve my problem, since it has occured
only when editing a perfectly well working formula...

How about the calc mode of the book ? Is it set to Auto ?
(Click Tools Options Calculation tab Automatic OK)

Have to check this one out on monday when I'm back at the office...

Kimmo