[F8] limit scroller

[psurrena]

I have a issue with my scroll arrows. When dragging the scroll bar is stops at the initial X and Y. When using the up/down arrows, it ignores that boundary. How would you set that limit?

Thank you in advance.

scroller_mc.onEnterFrame = function() {
    current=((this._y - initialY)/scrollLength*maxScroll);
    news_txt.scroll = current+1;
}

scroller_mc.onPress = function() { this.startDrag(false, initialX ,initialY, initialX, endY); }
scroller_mc.onRelease = function() { stopDrag(); }
scroller_mc.onReleaseOutside = function() { stopDrag(); }

up_mc.scroll = function() {
    this._parent.scroller_mc._y--;
}

up_mc.onPress = function(){
    this.int_down = setInterval(this, "scroll", 0);
}

up_mc.onRelease = up_mc.onReleaseOutside = function(){
    clearInterval(this.int_down);
}