Bug Report

• Package version(s): office-ui-fabric-react": "^2.20.3-vsts.2

Products/sites affected: (if applicable)
VSTS

Describe the issue:

When the dropdown is expanded, and tab key is pressed, focus goes to the address bar of the page.
It should have closed the dropdown and focussed on next element.

Actual behavior:

Focus is lost, it usually goes to the top bar of the browser.

Expected behavior:

It should have closed the dropdown and focussed on next element.