Gets he value added to or subtracted from the Value property when the scroll box is moved a small distance.
Returns
A numeric value. The default value is 1.
Remarks
When the user presses one of the arrow keys, the value property changes according to the value set in the small_change property.
You might consider setting the value of small_change to a percentage of the value of the height (for a vertically oriented track bar) or width (for a horizontally oriented track bar) property. This sets the distance your track bar moves proportionate to its size.