Brew MP 1.0.2
This function is used set the threshold percentage that is used to determine
when two invalidation rectangles should be joined or kept separate.
It will use the union if
(Area of Rect1 + Area of Rect2) > (Threshold% x Area of Union)
In other words, a smaller threshold encourages using the union of the
rects, while a larger threshold will track each rectangles. For the border
cases, a threshold of 0 will always use the union of the rects while a
theshold of 100 will only use the union of the invalidate overlap.
Pointer to the IWidget interface object.
Value to set to the property