Before patch Q maybe or whenever the sound engine was re-worked
If LFS was out of window focus e.g alt tabbed to browser window or IRC or some other app , You could still hear the game running.

Will this ever be restored ?

So that if i get PM in MSN or im in IRC , i can hear people joining server, it has become quite a frustration to have people join , then leave because they pressume im idling/afk which im not , i just dont hear them join.

Or could it be possible to have some audio beep/buzz if LFS window is not in focus on messages or player connect ?

+1 for the extra bleep, but don't bring back the constant noise. Hearing cars was annoying.

I think this is the the default behaviour of DirectSound instead of WaveOut. If WinAmp can make DirectSound still work when it's not active, I'm sure LFS could if Scawen saw the need.