Just a comment. These function signatures that have different numbers of arguments depending on context is very confusing. Is this explained somewhere? I've already found the comment that ML object methods don't implicitly have a reference to 'this' (the object) but I'd like to see more examples on how to deal with this. For example: addlistener(toggle_button_obj,'ToggledState',@(h, event) handleEvnt(RTTobj,h, event)); Using an inline ftn handle to translate the method signature from (RTTobj,h,event) to (h,event) ?? I'd like to know more about why when and where I need to do such things.