For everyone, this addon is still working via GreaseMonkey or other script manager and I suggest you migrate to that. For some reason, Firefox won't update this one. And yes, the button UI is fixed there. Thanks for the great work Dmitry!

tuff

i bin using this addon for years but now that youtube have removed the dislike button on shorts maby this can be a new feature to add it back in this addon ? :)

I give that 5 start cause it was doing its job for a long time. But we need an update urgent.