Accessibility issues adding/removing pull request reviewers

When removing a reviewer from or adding a reviewer to a pull request:

• There are no remove links
• When a name is typed, no list appears

Latest version of NV Access' NVDA screen reader is being used on a Windows machine via the latest version of the Firefox browser.

Additional Details

• Firefox tends to lag and sometimes crash to the point where scripts from Bitbucket stop responding all together.
• Happens in pull requests or commits with approximately more than 20 files.