The UI for multi-file upload has changed as compared to v1. Now we do not have a visual drop zone.
So in v2, in order to guide the user while dragging and dropping files, the application should show the interaction of the drop action with the sub-items section.

inaki.juaniz-velilla@ez.no - can you please provide the expected interaction as well as the design for this story for both the sub-items as well as the modal window.