Playing a sound when the Window of MUSHclient is in the background

I often do other things while mudding, such as writing stuff, doing calculations or just browsing the internet.

I noticed that sound triggers do not get played when the MUSHclient window is in the background, only when it is in the foreground and has the focus.

Is there a way to make it play sounds when it neither has the focus nor is in the foreground? Would be awesome to get a sound reminder e.g. when one gets attacked. ;)

In the immediate window (Ctrl+I), you can enter this:

This works. How can I add this permanently ?

Just save your world file. Ctrl+S.