AS3 localToGlobal returning seemingly random x values - actionscript-3

Question

I have a main timeline with a scroll bar. The sub timeline contains a long string featuring buttons. I am using localToGlobal to determine where the buttons are located on the stage so I can have relative information pop up on the left or right hand side of the button depending on where the pop out may fall on the stage. Everything seems to work until the scroll bar moves the timeline too much, then the x values traced seem to return random values.
Any idea on how to get a consistent result of x value that just shows where I click on the stage so I may tell the pop out to go right if it's too close to the left edge and left if it's too close to the right edge? I have the structure laid out it's just the x value on the main stage that seems to be wonky.
Here is the AS on the timeline.
stop();
import flash.events.MouseEvent;
import flash.geom.Point;
//attach listeners to all your buttons
btn19980930.addEventListener(MouseEvent.CLICK, showPopup);
btn20110928.addEventListener(MouseEvent.CLICK, showPopup);
btn20111214.addEventListener(MouseEvent.CLICK, showPopup);
btn20120110.addEventListener(MouseEvent.CLICK, showPopup);
//define space in the timeline movie clip
var leftEdge:Number=360;
function showPopup(evt:MouseEvent){
//figure out which button got clicked
var buttonClicked = evt.currentTarget;
//first get the local position of the button
var localPoint:Point = new Point(buttonClicked.x, buttonClicked.y);
//then calculate the buttons position in the global space
var buttonGlobalPoint:Point = buttonClicked.localToGlobal(localPoint);
trace(localPoint);
trace(buttonGlobalPoint);
if (buttonGlobalPoint.x < leftEdge){
gotoAndStop(buttonClicked.name + "_right");
} else {
gotoAndStop(buttonClicked.name + "_left");
}
}

Answer 1

You should be able to get the global coordinates of the mouse event with stageX and stageY:
var stageMousePoint:Point = new Point(evt.stageX, evt.stageY);

Answer 2

One thing that did finally work, although it's messy and overly bulky is to copy the section of script for each button to be able to give each button a different "leftEdge" parameter so even if the buttons vary in size and in anchoring, they react to a custom number. I know there is probably a way to condense the script but I am moving forward with what I know.
// button 01
//attach listeners to all your buttons
btn19980930.addEventListener(MouseEvent.CLICK, showPopup);
var leftEdge:Number=200;
function showPopup(evt:MouseEvent){
//figure out which button got clicked
//figure out which button got clicked
var buttonClicked = evt.currentTarget;
//first get the local position of the button
var stageMousePoint:Point = new Point(buttonClicked.stageX, buttonClicked.stageY);
//then calculate the buttons position in the global space
var buttonGlobalPoint:Point = buttonClicked.localToGlobal(localPoint);
//trace(localPoint);
trace(buttonGlobalPoint);
if (stageMousePoint.x < leftEdge){
gotoAndStop(buttonClicked.name + "_right");
} else {
gotoAndStop(buttonClicked.name + "_left");
}
}
// button 02
//attach listeners to all your buttons
btn19990224.addEventListener(MouseEvent.CLICK, showPopup);
var leftEdge2:Number=215;
function showPopup2(evt:MouseEvent){
//figure out which button got clicked
var buttonClicked2 = evt.currentTarget;
//first get the local position of the button
var localPoint2:Point = new Point(buttonClicked2.x, buttonClicked2.y);
//then calculate the buttons position in the global space
var buttonGlobalPoint2:Point = buttonClicked2.localToGlobal(localPoint2);
//trace(localPoint);
trace(buttonGlobalPoint2);
if (buttonGlobalPoint2.x < leftEdge2){
gotoAndStop(buttonClicked2.name + "_right");
} else {
gotoAndStop(buttonClicked2.name + "_left");
}
}

Answer 3

Even better, Cadin hinted in the correct direction of using the mouse, but rather than worrying about where the mouse is exactly i only needed to know if the mouse was on the left or the right side of the screen within a certain threshold. The i could decide which side the popout would appear.
stop();
import flash.events.MouseEvent;
import flash.geom.Point;
import flash.display.MovieClip;
import flash.display.DisplayObject;
//attach listeners to all your buttons
btn19980930.addEventListener(MouseEvent.CLICK, showPopup);
btn19990224.addEventListener(MouseEvent.CLICK, showPopup);
btn20010105.addEventListener(MouseEvent.CLICK, showPopup);
btn20050702.addEventListener(MouseEvent.CLICK, showPopup);
btn20060000.addEventListener(MouseEvent.CLICK, showPopup);
btn20060629.addEventListener(MouseEvent.CLICK, showPopup);
btn200720080000.addEventListener(MouseEvent.CLICK, showPopup);
btn20080229.addEventListener(MouseEvent.CLICK, showPopup);
btn20090307.addEventListener(MouseEvent.CLICK, showPopup);
btn20091209.addEventListener(MouseEvent.CLICK, showPopup);
btn20101125.addEventListener(MouseEvent.CLICK, showPopup);
btn20110120.addEventListener(MouseEvent.CLICK, showPopup);
btn20110312.addEventListener(MouseEvent.CLICK, showPopup);
btn20110729.addEventListener(MouseEvent.CLICK, showPopup);
btn20110316.addEventListener(MouseEvent.CLICK, showPopup);
btn20110815.addEventListener(MouseEvent.CLICK, showPopup);
btn20110909.addEventListener(MouseEvent.CLICK, showPopup);
btn20110928.addEventListener(MouseEvent.CLICK, showPopup);
btn20111214.addEventListener(MouseEvent.CLICK, showPopup);
btn20120110.addEventListener(MouseEvent.CLICK, showPopup);
var initialX : Number = 496;
function showPopup(evt:MouseEvent){
//figure out which button got clicked
var buttonClicked = evt.currentTarget;
// not finished, we need to calculate using timeline_mc x and width
if (stage.mouseX <= 400){
gotoAndStop(buttonClicked.name + "_right");
} else {
gotoAndStop(buttonClicked.name + "_left");
}
}