I didn't look into this in detail, but would it be possible to just always switch to using a patch artist, using a strategy similar to#24455/#25247 ("auto-switch back to the old kind if the user tries to access the object") during the transition period?

I'll look into it

Edit: Always using a patch gives us a problem when someone tries to customize the box usingsetp or tries to call a Line2d method on the box, like in theIID bootstrap example. I don't see a way around that.

Edit: Always using a patch gives us a problem when someone tries to customize the box using setp or tries to call a Line2d method on the box, like in theIID bootstrap example. I don't see a way around that.

The point would be to auto-backconvert (with warning) to the "old" form if that happens, as in#24455/#25247.