Initially, throbbers tended to be quite large, but they reduced in size along with the size of toolbar buttons as graphical user interfaces developed. Their usefulness declined somewhat as most operating systems introduced a different pointer to indicate "working in background", and they are no longer included in all web browsers. Furthermore, even web browsers that do use them depict images less elaborate than their predecessors. Many browsers — like Mozilla Firefox, Opera and Google Chrome — place a small throbber in the tab while a page is loading and replace it with the favicon of the page when loading has completed.