Hi thats a Firefox problem when using Adblock, which probably is the most common Addon used! Unortunately, in its protection mode, it stops Youtube and others working. I just found out earlier that by allowing web sites (mine with OG) that many problems go. Now I see all icons, and some of the other problems go except for the Overview problem. I will set up temporary permissions for you on our website so you can see what I mean.
Will PM you later.
Cheers,
Alistair.