Ok I think that I got it!!! Just modify the script in
Object.Width = 40 + 100 * (y / System.screeWidth) instead (x / System.screeWidth)
Now only change it size only when go up or down. That is perfect.
Now have a question. Due to the first statement
When the user move the object to any new position, the object change its size, great.... but when the user restart Windows... the object back to the original position.
How can I keep the last position used?