I used to find this annoying, but once I got over myself and my resistence to change I quickly started to find it extremely useful. Before, if I wasn't paying attention to the inactive mIRC window, I wouldn't know if someone said something in the active channel and would completely miss conversations due to not noticing a highlight... now I do. I don't think this behaviour is going back, so I suggest you do what I did: get over yourself, embrace change, and be happy.
