How to reproduce:
1.Open Mirc 6.12(may work on 6.1,6.11 not yet tested)
2.Make sure what the systray option("Place mIRC in tray when minimized") is enabled
3.Type /timer 3 2 /window -a @annoyingwindow
4.Minimize(to the systray) the mIRC window

Result: After execution of /window -a @annoyingwindow the mIRC window was maximized and show you the @annoyingwindow ..

In the mIRC 6.03 and older after execution of the command the mIRC window remain minimized to the tray !

Solution: new switch to the /window command or fix -a switch..

Tested on mIRC 6.12 Win98SE 450mHZ