When we add any UI or container in WinForms, the later added component comes over the earlier added components, we can say it is in a higher layer.
How to change tha
Is it when you load components dynamically in code or in the designer? If it is in the designer you can use the Format -> Order -> Send to Back and Format -> Order -> Bring to Front commands. Send to Back and Bring to Front are also available in the context menu when you right-click a control, as well as in the "Layout" toolbar that should appear automatically when you work in the forms designer.