User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8) Gecko/20051217 Debian/1.5.dfsg-2 Firefox/1.5 Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8) Gecko/20051217 Debian/1.5.dfsg-2 Firefox/1.5 Example: I'd like to use 'xchat -a' to open any irc links I may click. If I make network.protocol-handler.app.irc=xchat -a , firefox will tell me there it does not know how to open the address, because the protocol is not associated with any program. If I make network.protocol-handler.app.irc=xchat --no-auto , firefox will tell me there it does not know how to open the address, because the protocol is not associated with any program. If I make network.protocol-handler.app.irc='xchat --no-auto' , firefox will tell me there it does not know how to open the address, because the protocol is not associated with any program. If I make network.protocol-handler.app.irc="xchat --no-auto" , firefox will tell me there it does not know how to open the address, because the protocol is not associated with any program. HOWEVER, If I make network.protocol-handler.app.irc=xchat, the link will open properly (although xchat won't behave how I'd like it too). Reproducible: Always Steps to Reproduce:

What about if you specify an absolute path to xchat (i.e. beginning with "/").

Scratch that, it won't work either. The code doesn't deal with command line parameters.

This is really bad, especially since Firefox 3.0 doesn't seem to obey gnome url-handlers any more like Firefox 1 through 2 did.

I guess a workaround might be to create a shell script "/some/path/start-xchat" that starts xchat with your additional options and passes the URL. Then set network.protocol-handler.app.irc=/some/path/start-xchat (But, I can't get network.protocol-handler.app.foo to work at all in a XULRunner 1.9 app...)