Can't change a Property's Type, silently fails

(Missing Feature, To be Fixed , Priority: Low, Test Status: No automated tests yet , Reported By Bad Link: Thing 3y284of not found, )
Properties
Summary: You can try to edit the Type of a Property in the Editor. But it (used to) silently fail to take. Now it usually just gives you an error after you try.
Alexx: I can't seem to change the Property Type of a Property after it's been created. That is, I can seem to change it, but after clicking "Done", Property Type reverts to what it was.
Justin: In fact, this shouldn't be legal at all for the moment. Changing the Type or Collection of a Property is enormously dangerous, if any Things are using that Property -- I haven't done much testing of the idea, but it's easy to see how it could result in very broken Things.
I believe the action plan (over the course of some months) will be:
  • Disable the ability to change the Type or Collection of a Property. Done
  • Disable deleting a Property iff it has any uses.
  • Provide a UI to show what is using the Property, and mass-remove the Property from those Things.
  • Enable changing Type or Collection iff the Property has no uses.
  • Allow changing the Type or Collection in specific, limited ways, with automatic transformation of values.
Justin: the first critical steps here are now done. You are explicitly allowed to change Types between the three textual Types; any other change will give you an error, as will trying to change the Collection. So reducing the priority here...