Thanks Wolfgang for the explanation.  \setupblank[fixed,big] works very well too.  Now for another question.  I have modified "SlideWithSteps" from

http://wiki.contextgarden.net/SlideWithSteps

It seemed not to like \eject and I replaced \phantom{ ... } with \setlayer[StepsHiddenLayer]{ ... } where StepsHiddenLayer is a layer created with

\definelayer[StepsHiddenLayer][state=stop]

See attached slide-with-steps.tex

This seems to work fine with itemized lists and even MetaPost figures (see foo.tex) but it fails with multiline equations (bar.tex) which are both attached.  I would like a solution that would allow me to reveal each line of a multiline equation.

Troy