Compare with a standard dropdown.

Steps

1. Open test.php
2. On the 'Tags' field, press down
3. Press Escape

Expected behaviour

1. The list is closed
2. Focus is returned to 'Tags' field

Actual behaviour

1. The list is closed
2. Focus is lost (this can be confirmed by pressing tab)

Pressing escape once the list is closed should lose focus, but when the list is open the focus should be returned to the input element which opened it.