set the thumbPosition of scrollbar 1 to 400
set the thumbPosition of me to (3 * the thumbSize of me)
Use the thumbPosition to move a scrollbar's draggable thumb when the content it controls is scrolled, or to check where the thumb has been dragged in order to scroll the content.
Value:
The thumbPosition of a scrollbar is a number between the scrollbar's startValue and endValue.
By default, the thumbPosition property of newly created scrollbars is set to zero (the default startValue).
Comments:
The thumbPosition is the location of the top edge (for vertical scrollbars) or left edge (for horizontal scrollbars) of the scrollbar thumb, using the scale set by the scrollbar's startPosition and endPosition properties.
If the style of the scrollbar is scale, the maximim thumbPosition, when the scrollbar thumb is all the way to the bottom (for a vertical scrollbar) or right (for a horizontal scrollbar), is the endValue.
If the style of the scrollbar is scrollbar or progress, the maximum value of the thumbPosition is the scrollbar's endValue minus the thumbSize.
