Comment 2 for bug 2061004

Looks like using mousedown rather than click on the ul might work around the issue.

However, per https://adamsilver.io/blog/building-an-accessible-autocomplete-control/, a better approach might be to:

- add a keydown handler on the input that closes the dropdown when the user tabs away from the input
- add a document-level click handler that hides the drop-down if the users clicks outside of it
- add something similar for touch events