Slider Bar Glitch

I adapted a horizontal slider bar to a vertical slider bar, and it appeared to work, but I noticed when I drag it down partially, and then release, I can drag it further down, but not back up. I have included my code below, with ''slide'' being the button that slides up and down the ''slider'' located in the navigation.tableu4 movie clip.

What did I do wrong to make the slider bar a ''one way trip'' and how do I ''buy it round trip tickets''?

----

onEnterFrame = function(){

?var y_num:Number = navigation.tableu4.slider.slide._y;
?
?navigation.tableu4.slider.slide.onPress = function(){
?startDrag(this,false,this._x,285,0,this._y)
?y_num = navigation.tableu4.slider.slide._y;
?}
?navigation.tableu4.slider.slide.onRelease = navigation.tableu4.slider.slide.onReleaseOutside = function(){
?stopDrag()
?}
?onMouseMove = function(){
?updateAfterEvent()
?}
?
?navigation.tableu4.backscreen.backslide._y = 30 - y_num * 1.618;

?
?}

Slider Bar Glitch

?startDrag(this,false,this._x,285,0,this._y) needs to be startDrag(this,false,this._x,285,0,0)

problem solved.