Don't want the boss to catch you surfing the Web on company time? Don't want your teacher, classmates, roommate or significant other to see the Web sites you're viewing? With Panic Button, a single click of a toolbar button will quickly hide all Firefox windows -- bring them back by clicking a button on the Restore Session toolbar, and your browser session will be restored.
JSSh is a Mozilla C++ extension module that allows other programs (such as telnet) to establish JavaScript shell connections to a running Mozilla process via TCP/IP. This functionality is useful for interactive debugging/development of Mozilla application
intercepting requests and responses between my Web browser and the Web server via Tamper Data [while] Paros and Burp both have features [...] such as site spidering and vulnerability scanning.
More often than not, the extension is compatible, but the developer hasn't updated the version information in the .xpi install file - you can change the version yourself manually in install.rdf , one of the file you get by unzipping the .xpi file.
"In Mac Firefox, whenever you open a new window, it tries to place the new window slightly below the current window: this extension will move all new windows as necessary to fit on the screen."