I didn't like the way it worked either. I set windows screen saver to the blank screen saver. Then when Mala starts I started a background winbatch (you could do ahk) script that waited for the blank screen saver window to appear. When that happens I sent some joystick moves to Mala. That way Mala is always showing a different preview.
' Allow Windows to be exited with no warning
IntControl(12,1,0,0,0)
'Allow quiet termination:
IntControl(12,4,0,0,0)
cnt = 0
defaultString = "{DOWN}{UP}{DOWN}{UP}{UP}{UP}"
While @TRUE
cnt = cnt + 1
if cnt > 5 then
KeyString = DefaultString
cnt = 0
else
KeyString = "%KeyString%{DOWN}"
End If
WinWaitExist ("Blank Screen Saver", -1)
If WinExist ("MAME") <> @TRUE Then
If WinExist ("MaLa") Then
SendKeysTo ("MaLa","{DOWN}{UP}{DOWN}{UP}{UP}{UP}")
End If
End If
End While