Can't see combobox items when there is a large list

To recreate:

Just duplicate the demo for the autocomplete combobox and add more items to the <select> element.

Once the number of items displays larger than the browser window or it's parent element, the combobox is then positioned way off the screen and is unselectable. For my test, it was about 25 items, which is a pretty small list.

What should happen instead:

A maximum height for the list of results should be set and it should have scrollbars - just like a real OS combobox