How to add a banner window of a fixed height to a windows that supports docking?

My UI designer wants to put a banner at the top of a window that supports docking operations. The banner will occupy the entire width of the window and has a fixed height. Once in place and properly sized, its width is allowed to change as the container's width changes but its height must remain fixed and the banner must never be undocked. How can this be done?

If its height is fixed and it cannot be undocked, it really can't support docking operations. This panel should be placed outside of the SandDock layout.