Hello Geoff,
Sorry for the late response! Below is a code snippet you can use to disable/make-readonly a Picklist widget using both TPC 3.3 or TPC 4.0 apis:
$(function(){
//TPC 4.0+
var pl = tpc.find("gendercode");
pl.disable();
//TPC 3.3
var pl = findControl("gendercode");
pl.disable();
});
Let me know if this answers your question.
Regards,
Clinton