I don´t know what people are smoking here, but this is working for me on FF 54.0.1 x64, even while using "Enhancer for Youtube" at the same time.

At first I did try copying the Youtube address and add it to the filter, but that doesn´t work, you have to use the name channel, or just use the right click menu and add it, which is the easiest way to do it.

Absolutely no issues after using it for a month.

Thanks so much, Mr. Developer!