You can also consult your Status.log provided you have "Nicks on join" checked under IRC > Options.
Perhaps the "Nicks on join" feature should have an event droplist... Status / Channel / Both.
However, this would open the door to nearly EVERY raw event that is presently restricted to a specific window.
PS. "Nicks on join" should be renamed to "Show Names". This would be proper, as it is the output of the [color:000099]/names[/color] command.
