Why cannot bind to a member BlueprintAssignable Delegate self

Development Programming & Scripting Blueprint
, , ,
1

Hi,
Why i cannot bind to a member BlueprintAssginable delegate self ?

If B widget has a child A widget, and A widget has a member BlueprintAssignable dynamic multicast delegate D,
then B can listen from D but A cannot listen from D. There is no assignable delegate in archetype of A.
So I should add delegate and BlueprintImplementableEvent both for same purpose.

Is there any other way?