Setting the Scrollbar Thumb size

Question

I am attempting to work out the algorithm associated with sizing of the WPF Scrollbar thumb element.

The thumb element can be sized using the Scrollbar.ViewportSi

Answer 1

Here's a method that will override the thumb minimum width for all ScrollBars. There's 2 important reasons for using this setup.

1) This will not resize the ScrollBar RepeatButtons. (Why the style overrides Track)

2) This will only resize the thumbs for Track controls that are used in ScrollBars. (Why the Track style is contained in a ScrollBar style.