Why on earth would Canvas remove the mute button in the grade book. Any action I need to take that involves searching for procedures and having two screens open, one to follow lengthy instructions, and one to implements said instruction is plain nuts. Put the mute button back.
Do not give in to the compulsion to complicate your user interface. Yes this is not a question. It is advice but I spent too long trying to figure out how to make suggestion.
You had a good product. DO not make it harder to use.