Captain obvious to the rescue! To change mood, click upper right corner: change mood: then select one from the list via clicking it once: and then wait for it to update.
If that doesn't work, only thing I can think of, is toolbars which install on all the browsers. So uninstall one of the browsers, install it again and see if it works (because it should). :3
If still doesn't work, tell us what happens if you single click it?