Spec Drag n Drop

Hello
I would try to integrate the exemple Drag n Drop from
http://spec.st/docs/drag_n_drop/ at the tutorial Building UI with Spec,
so I have create a class in Pharo to try them and modify the code.

I have found some of problems, I'm not sure if it come from strange
configuration (i think about dragTransformationBlock: ), but it appear
on the both version (my class and the original code).

Marion,

1)
Reproduce:
Deplace the 'c' in the list of int, try to replace the 'c' in the list
of char
Error "nil not found in Orderred Collection"
- Proceed don't remove the c from the list and make arrives a nil, like
in the result deplaceReplaceC.png
- Abandon seems work well, but the next refreshing of the list (by
another move) make the nil appear too


2)
Reproduce:
Deplace the 3 in the list of char, try to replace the 3 in the list of
int (at its place)
Error " '3' not found in Orderred Collection"
- Proceed duplicate the 3 gives the result DuplicateNumber.png
- Abandon affect all number after the place, they "become" the previous
number (BadNumber.png). Try to move the 4 make an error because it don't
found 3, try to move the 5 make move the 4.


3)
Reproduce:
Deplace all items the list of int in the other
Try to move the 'a' in the empty list of int
Error "SubscriptOutOfBounds: 0"
- Proceed remove the a from the list, but don't make it appear
- Abandon seems work well