Admin related foreign key popup

When in the Django Admin and ForeignKeys are present, the '+' (add button) does not open a pop-up or separate window for user's to enter what they are wanting to add.

Reproduce the issue in Django Admin with a model containing a ForeignKey and click the '+' add button. No file or test is named in the issue, so first locate the admin-related entry point and verify the current browser behavior. Done means the button opens a popup or separate window where the user can enter the related object.

Written by the indexing model from the issue text.