I have yet to have a need to dynamically create messengers by passing in the messenger type into "Create Messenger", so the constant is usually just a waste of extra block diagram space. It would be nice for "Create Messenger" to have a polymorphic wrapper which removes the need for the constant, delegating that to the polymorphic selector on the icon. Of course, the original version could either live independently in an "advanced" subpalette, or as a selectable instance of the poly wrapper.
