Bootstrap uses display:none to control visibility of a dropdown, changing it to display:block when open.
Flat-UI uses opacity:0 and visibility:none.
The result is the same, but when you use a 3rd party bootstrap wrapper (eg ui-bootstrap), these differences break the dropdown in that it will be open but, but will still have opacity:0 and visibility:none.
Changing Flat-UI to use display:none fixes this.
change dropdown visiblity control to match bootstraps
please check the latest release, we have dropdown component completely rebuilt.