Your code would only work if you did the check during the 1 millisecond window where millis() ends in 000. You should check instead to see if the delay is equal to or greater than 1000. e.g.
if (currentMillis - blinkStartMillis >= blinkPeriod) //test whether the period has elapsed
Thanks. It seems to work.
But the main problem remains: Looks like i cant use time library with SmartMatrix, like if both re using the same timer.
Im just trying to: