KOF style supermove background flashes

when doing a super move in KOF usually a combo based one, i noticed the screen flashes white, but behind them

reading mugen documents i found that the value under = 1 makes this happen when using envcolor, here is an example

[State 3000, background flash]
type = EnvColor
trigger1 = movehit = 1
value = 255,255,255
time = 1
under= 1 ; remove this line if you want the screen to flash infront, but keep it for better effect.