[dev][dwm] Rule to don't manage a window?

[thuban]

Hello!
The thing I want to do, is to configure dwm in order it doesn't manage
some windows. Infact, the problem is when I launch dwm, when I cycle
throught windows, stalonetray can still be selected. And what I want is to
have stalonetray pasted in the background, over the status bar. Is there
any solution to do such thing?