Forum d’assistance Firefox

I'm having trouble using a particular site, that I used to be able to in particular clicking on sub menu's from a context menu if that is the correct term, meaning I cannot click an item/button to reveal a menu below it. From the image supplied there are 2 'menu's' with a < character that when clicked should reveal a sub menu of items, works in Edge/Chrome etc.. the only extension I have is Keeper.

Hey folks, I've been noticing something peculiar with Firefox that's been bothering me lately. Whenever I try to watch videos on YouTube in resolutions above 1080p, they tend to randomly buffer. It's quite frustrating, especially when I know my internet connection is stable and other browsers don't seem to have this issue. Has anyone else experienced this problem with Firefox? And if so, do you have any tips or solutions to share? Thanks in advance for any insights!