[graemep]

Two examples that come up a lot for me:

1. filtering a drop down list by typing rather than scrolling through lots of options to pick one 2. Rearranging items with drag and drop

The excessive stuff is requiring a whole lot of scripts and resources to load before you display a simple page of information.

[LtWorf]

Doesn't the combo box input field already do this?

[graemep]

You are right, it does.

A better example would be dynamically loading the list of options where it is very long and loading the entire list would make the page size much larger.