I think this has probably been a problem for a while but I just didn't see it until I started tweaking Firefox 4. There are multiple Java Console addons listed when I go into Tools, Addons. (These are not listed in Windows 7 Control Panel Programs.) Within Firefox, I disabled all but the newest version. Exited Firefox. Then went to the Firefox Folders. In Windows 7 the extensions are stored here: C:\Program Files (x86)\Mozilla Firefox\extensions I deleted the relevant extra Java Console folders except for the newest version.