Decide on behavior when changing an element in a sorted view

[busti]

When an element is moved in the source collection of a sorted view, the change might result in a move in the sorted representation.
For example, if we sort Seq("Dog", "Cat", "Giraffe" "Mouse") by name we end up with:

• Cat
• Dog
• Giraffe
• Mouse

if we now apply an Update(2, "Zebra") to the source, we would end up with:

• Cat
• Dog
• Mouse
• Zebra
  where 2 and 3 switched places, but we could also say that 2 was removed and then there was a new insertion at index 3
  So, which will it be?