I've a little bug since the last update of Adium, everytime I hide the window, when it appears again, the window goes down of few pixel. After some hiding and appearing, the window is off the screen.
This is a bug in Adium 1.2.5 which only occurs on Mac OS X 10.4 when the message window toolbar is visible. It has already been fixed for the next release of Adium. In the meantime, you can work around it by clicking the pill button in the top-right corner of the message window, which will hide the toolbar in that window.