Hello! Thank you very much for your help! When I´m playing videos on my regular firefox after 2-3 minutes the player stops, saying "This page slows firefox. Please stop playing this video". But this are completely common videos, not youtube or the normal tv-news (as for example "Tagesschau": https://www.ardmediathek.de/live/Y3JpZDovL2Rhc2Vyc3RlLmRlL2xpdmUvY2xpcC9hYmNhMDdhMy0zNDc2LTQ4NTEtYjE2Mi1mZGU4ZjY0NmQ0YzQ?xtor=CS1-322-[navi]-[all]-[content]-[text] but yes at pages like e.g.: https://www.99.media/de/jeden-tag-zaehlt-maria-die-pilgerinnen-und-pilger-die-auf-dem-jakobsweg-vor-ihrem-haus-vorbeigehen/ Thank you very much again, Philip