IVE: Easy to move items to be nested in a function

It should beasy to move parts of a (large) diagram to a function, as nested items.

Possible implementation A:
Draw a new function around the affected functions (interfaces,...). When the new function is created, all the other items are moved to be nested inside this new function.

Possible implementation B:
Multiselect all items. Add an action to move them inside a new function.

Note: The connections should still remain. So from now nested, to the new parent, to the original other function(s).