In Edge 40.15063.674.0 (EdgeHTML 15.15063) Popup will NOT show FontAwesome icons meaning froala toolbar will be empty.
It will start Froala below and after this clicking again "Open Froala in Iframe" will make FontAwesome icons to load in iframe too.
To Start over just Reload this page.
IMPORTANT: You need to close Developer Tools as if open it will work just fine and you won't be able to duplicate!