How do you build a scroll bar that can pan and zoom?

Question

I own a charting application (exe, no source) with a horizontal scroll bar that can be slid from side-to-side to view the entire chart (normal scrolling action). This scroll bar also has a grip at each end that can be used to expand/shrink its length, and thus expand/shrink the scope of the current viewing area (resulting in a zoom-in, zoom-out action). Does anyone know if this dual-action scroll bar is built from a set of "stock" functions in .NET, or does it require a fully customized approach? I would like to recreate this control in C#, and I would appreciate any information or example(s) that could help get me started. Thanks.