Just noted something else this morning, still using mIRC 6.34.
After I was connected to the first network, I then proceeded to type /server -m ircserver.com, and then switched to another window, leaving mIRC as an inactive window.
While it continued to join channels according to the perform, the button was still showing as I was having the status window open, while I in fact had the #lunara channel opened.
It switched to showing #lunara as the active button immediately when I selected mIRC as the active window.
Is this a bug, or 'intended'?