I need to implement a zoom feature with the middle mouse wheel (like Google Maps, Google Earth, etc) on a CNiGraph. So if the mouse cursor is over the graph, and the user scrolls the mouse wheel forward, the graph zooms out; if he scrolls the wheel backward the graph zooms in. My CNiGraph already supports the lasso zoom, and half-scale zoom in / double-scale zoom out with toolbar buttons and hot keys, but the customer (boss) always wants more!!! I'm using Measurement Studio 8, Visual C++ in Visual Studio 2005. If you have any hints, links, or code that would help, I'd appreciate seeing it! Thanks!