Don't Rely on Stage.width and Stage.height
Stage.width and Stage.height sometimes return a value of 0 when run in IE(Internet Explorer) .
This is especially true on the first frame of the timeline or when a new URL is opened.
Where possible saving the dimensions as a static variable. When you need the dimensions to update to reflect changing browser dimension using onResize() you should check the value of Stage.width and in case it is returning a value of 0. If that is the case add a call(setInterval onEnterFrame) to keep checking for proper value.
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If anything is unclear or just plain wrong let us know and should ammend it pretty sharpish. If you visited the page with a particular question leave it and if it's flash related I'll try to answer it.