ScrollWheelWithSelectionStyle resize at runtime

I have a ScrollWheelWithSelectionStyle instanciated from the designer, so it is placed inside the ViewBase, with a certain size.

What I whant is to be able to resize it in height from the View. This is because when instanciated it is set to hold 4 elements, so it's height is ITEM_HEIGHT * 4, but in the View it might contain less than 4 elements.

if I try a ScrollWheel.setHeight(_SOMETHING_) it crashes.

Also tryed to change the number of elements from 4 to (let's say 3), but the items appear ofsetted from the top of a height equale to the height of the missing element.

What is the correct way to resize a ScrollWheel at runtime ?

Thanks