> One of the options (if the addon is an xpi) is to do a file -> open and > locate the file and that should fix it. > They're supposed to be in .xpi format, not .jar I thought theme is a kind of those addons. sorry > Also have a look at MR Tech [1] MR is just the right thing I'm looking for,it at last gives me a "Install" Button~~ Thank you guys very much!!