Thanks for leaving feedback! Unfortunately, there isn't much I can do about this. Resizing div tags tends to cause more problems than it solves (though I can add it to the list of possible tags - go to the github and make a comment there if you want that). Regarding the jumping, the way Firefox rerenders the page is not something I can control. If you find another add-on that handles something like this better, do let me know though. I'd gladly look into how it does it and implement it here.