[NTG-context] Recomputing useMPgraphic in footers

Hello, I have \defineoverlay[Wave][\useMPgraphic{Wave}] \startuseMPgraphic{Wave} ... \stopuseMPgraphic \setupbackgrounds[footer][text][background={Wave}] The problem is that the graphics is not re-computed on every page, although I pretty convinced it should. On the opposite, when I set \setupbackgrounds[text][text][background={Wave}] it works perfectly well. (The difference is in [footer] vs. [text].) An ugly workaround is to call \setupbackgrounds on every page, but it's not nice at all. What went wrong? Thanks, D.A. -- Trust no man, not even your brother With hair one colour and beard another -- Ty Semaka (The Plaid Tongued Devils): never drown a cat