Can't manage the order of Properties on customized Things

(Incomplete Feature, Investigate , Priority: Medium, Test Status: No automated tests yet , Reported By Justin du Coeur, )
UX
Summary: That is, if I create a Simple Thing, and add Properties to it, it's impossible to control the order of these Properties.
This is actually a design bug, not a UI one -- since a Thing can't introduce its own Instance Props, there's no way to store the decision.
More immediately, though, we shouldn't be showing the grab handle if we can't use it.