Revealing mistake: In the scene with www.planetsolomon.com, you can see that it is a pre-filmed video (not a live stream as he said), as it has a time slider and play/pause controls etc. (00:13:05 - 00:13:45)
Suggested correction: During streaming, any video player can be used. Meaning "play" or "scroll" buttons are still visible, just not functional.
The color of non-functional buttons will be muted. You can see in the picture that the stop button is solid black, indicating that it is functional. The marker on the status bar is also partially advanced. In a live stream, the marker would remain at the beginning position unless someone paused the stream, in which case resuming play would cause the marker to advance in order to catch up to the delay. In this scene, Dr. Solomon is teaching his class and interacting with his students, meaning no-one paused the stream.