WebView uses the ScrollBar control to render an HTML scrollbar control. When in an html page the "overflow:scroll" css property is specified the page always shows a scrollbar,
not depending on the page size. Top browsers (ie, firefox, chrome) render such a scrollbar without a thumb when the content fits the page size (see the screenshot attached).

The ScrollBar control doesn't allow WebView to behave the same way. In this scenario the scrollbar is rendered with a thumb of max size.