[Answered ]-Django searchable drop down for ForeignKey widget

The 3rd party component Django Ajax Selects does exactly what you are looking for.

I played around with django-selectable as well, but found django-autocomplete-light (https://github.com/yourlabs/django-autocomplete-light‎) easier to use and more flexible for what I wanted to achieve.

Perhaps it can be useful to you as well.