After upgrading my Win10 to 1607 my right click > open message in browser functionality is semi-broken. With IER enabled, that context menu option provides me with the choice of it IE or Firefox. The IE option works, the FF one does nothing. With IER disabled, the "Open in browser" option successfully invokes the system default browser (Firefox). I have uninstalled/reinstalled FF and toggled the system default browser (IE > system restart > FF system restart) but no joy. Anyone have any other suggestions on how to fix this?