[NTG-context] Why does \doifsomething think there is content?

I am creating a book that presents readers with a list of recommended materials. If materials are listed, then its displayed under the \subject{Materials} heading in a simple itemized list. I'm using \doifsomething{} to check if any items are listed. The problem I'm having is, when fed a blank macro, `\define\needsoven{}` it thinks there is content, so it displays the "Materials" heading, but an empty list. I have a custom macro that determins "if oven is needed" independent of these other items. So I need `\define\needsoven{}` to be regarded as nothing. How can I get \doifsomething{} to think \define\needsoven{} is an empty value? --Joel My minimal working example is below: \define\needsoven{} \define[1]\materialsneeded{%         \doifsomething{#1}{             \subject{Materials}                 \startitemize                     #1                 \stopitemize         }         } \starttext     \chapter{Recipe 1}         \materialsneeded{\needsoven}                  \subject{Instructions}                      Spread peanut butter on sandwich.              \chapter{Recipe 2}                  \materialsneeded{\item pizza cutter \item stove}                  \subject{Instructions}                      Preheat oven to 450 degrees F.              \stoptext