''[Locked as a duplicate of https://support.mozilla.org/en-US/questions/1352314. Please follow up there, thanks.]'' Thanks Cor-el for replying with advice on how to use about:config to ensure the screencapture was toggled correctly. It wasn't and I corrected that. Now I have the icon in the toolbar and on the right click menu but when I attempt to use them all I get is a popup menu with a large black X in it and nothing can be done with it. Also, on the toolbar items that are added to it all appear in the overflow and there is no way of getting them to appear on the screen by reducing the size of the search bar. I've been using firefox ever since it first appeared and I've never had problems like this before.