It is possible to embed a Youtube video in a GUI.
To do so, use the web tool, but for for the URL use the embed URL for the video instead.
So instead of http://www.youtube.com/watch?v=JuMjMSPlGSc the URL becomes http://www.youtube.com/embed/JuMjMSPlGSc
There is an example here: https://github.com/CommandFusion/DemoUserInterfaces/tree/master/YouTube