So, I would just say, that it should probably check wether it's in a landscape environment, so as the paper is oriented bass-ackwards, as to not stare naïvely at the \textwidth, as defined by the paper size.
Sorry it took me a moment. Esko.
I agree that gnumeric shouldn't care, the fact is, is that it assumes
that the \textwidth in the document is correct, the landscape
environment doesn't change (as far as I know) the value for the
textwidth, and thus the macrosystem to scale the width correctly fails,
and thus I would get a textwidth that would actually match the height of
a landscape-oriented document.
