not functioning inside RSS View

Hello ,

very big thanks for this add-on (i finally could switch from FF 52 ESR to FF 60 ESR -32bit).

It seems that the add-on is not functional on RSS View-overview sites like

https://www.rt.com/rss/

or 


https://www.techpowerup.com/rss/news


atleast on my computer running windows 7 64bit (FF ESR is in 32Bit Mode).



