[NTG-context] understanding the \feature command

Dear list, I have the following sample: \definefontfeature [f:protrusion] [protrusion=quality] % \definefontfeature [f:noprotrusion] [protrusion=none] \setupalign[hanging] \starttext \feature[+][f:protrusion] \input knuth \blank[2*big] \feature[-][f:protrusion] \input knuth \stoptext Is there any way to enable and disable character protrusion in the previous sample other than setting a diferent alignment for each paragraph? Many thanks for your help, Pablo -- http://www.ousia.tk