Marco, thank you, and thank you for the testing.

A brief, extremely simple self reminder, about MoI in general:
Hidden edges or curves cannot be selected until they are unhidden, using Hide or Styles of Types, or some other script. :-)

It seems that objects saved by MoI and reloaded may have a few previously hidden edges unhidden.
It seems that objects saved by Max's ObjLibrary , and reloaded with customUI, have ALL previously hidden edges unhidden. (?)

- Brian

I assigned Shortcut key "M" to _CurveMidpoint.