How to create a drop down button similar to the "+Add" button in views?

Hi,

I am trying to create a drop down button similar to the “+Add” button in views, without success.

Attached please find the screen copy of the views example, and could anybody please suggest how to achieve this?

Thanks.

Regards,

foredoc

Drupal version: 


Source: https://www.drupal.org/taxonomy/term/22/feed