The slider control provides this message to give the application the opportunity to provide a custom slider shaft, custom ribbon strip, custom slider arm, and custom background. The application can specify one or all of these items and is given the opportunity to do so.

The slider control window procedure generates this message and sends it to its owner, informing the owner that an item is to be drawn. The owner is then given the opportunity to draw that item, and to indicate that an item has been drawn or that the slider control is to draw it.