[NTG-context] disabling italic correction

Dear list, I have the following sample: \definefontfeature[default][default][itlc=yes] \setupitaliccorrection[global] \starttext {\em of}) \setupitaliccorrection[none] {\em of}) \stoptext Which is the way to enable and disable italic correction in the same sample? Many thanks for your help, Pablo -- http://www.ousia.tk