Combobox Selected Item not visible when using arrow keys

[PR33T0]

Describe the bug
When navigating in a combobox with your keyboard (arrows). The list does not scroll to keep your selected item visible.

To Reproduce
Steps to reproduce the behavior:

1. Go to 'Documentation page combobox/form'
2. Click on the first combobox with more items then shown (need a scroll bar)
3. Use keyboard arrow to navigate down.

Environment

• Browser [chrome]

[karan-kang]

Releasing in v0.12.0