I think the suggestion is to use a tab for each network, then have the switchbar IN THAT TAB with just the channels for that network.
Which I think is what Bitch-X does?
I rarely have more than a couple of channels on each network open (and I don't use mIRC for mass file transfer, warez, mp3z etc. etc.), but a tabbed interface would nevertheless be a lot "cleaner".
PM
