xchat with firefox integration not working in 11.4 (working in 11.3)

First of all I am actually really happy with 11.4 and all of the hard work gone into it - so sorry for all of the threads I’m making - I’m willing to help fix any of the problems I have raised if I’m able.

With a default 11.4 (64bit) install selecting Gnome desktop environment.

Go to monotone in Firefox 4 - and click on the “IRC” link on the right hand side in the “Improve it” section.

In 11.3 a popup window would appear with “xhat” in the list, with an organge X icon - I then click OK, and xchat would load, connect to the relevant server, and join the relevant channel and be ready for chatting.

In 11.4 the dialog pops up with “xchat” in the list, but with no icon. Clicking OK does nothing. Selecting xchat as a custom application just loads xchat - and does not connect to the relevant server.

I guess this is a Firefox 4 problem ?