Shadow DOM Issue: Selection Dropdown Hangs Open When Clicked Elsewhere On Page

As a user of Select2, I would like the dropdown menu to close when I click elsewhere on the page because this is the expected and natural behavior of selection dropdowns.

Expected Behavior:
When a the selection dropdown is open and a click happens outside of the dropdown menu, the dropdown menu should close.

Actual Behavior:
The dropdown does not close when a click event occurs outside of the open dropdown menu.

Steps To Reproduce:
Create a Select2 element in the Shadow DOM and configure it to open a dropdown menu when a user is selecting an option. Click outside of the dropdown menu and Select2 element. The dropdown menu will hang open.

Notes:
I consider this a bug and not a feature request because it seems that the default behavior of Select2 is that clicking outside of the dropdown menu closes it.
JSFiddle: https://jsfiddle.net/mslocum/kfqd7nga/

Start with the linked JSFiddle and reproduce the behavior using a Select2 element inside Shadow DOM. Trace how clicks outside the dropdown and Select2 element are handled, then verify that the dropdown closes when the outside click occurs.