Views-based autocomplete vs Add links

Preconditions:

• A site with (let's say) 4 content types.
• An entityreference field:
  • which accepts linking only to 2 of those content types;
  • is configured to display "Add" and "Search" links beneath the widget via references dialog;
  • with a views-based autocomplete widget (eg. for displaying the content type besides the node title on the autocomplete search results).
• The view behind the autocomplete has a contextual filter for the content types, to allow different fields using the same view with arguments like "firsttype+secondtype".

Problem:

• The "Add" link is not present.

Solution:

• Instead of a contextual filter on the view, add a real type filter to that display of the view which is being used on this field. With this approach, references_dialog will have information about the acceptable content types. With the contextual filter/argument approach, references_dialog cannot have this information, so it is not displaying the "Add" links.

(Couldn't find other places like a documentation page or a README to add this information, that's why I'm posting it here.)