Closes other menus in the NavBar before opening one of them. Fixes #265.
Closes other menus in the NavBar before opening one of them. Fixes #265.

zkoehne/Office-UI-Fabric,OfficeDev/Office-UI-Fabric,OfficeDev/Office-UI-Fabric,waldekmastykarz/Office-UI-Fabric,zkoehne/Office-UI-Fabric,waldekmastykarz/Office-UI-Fabric