When developing Windows Mobile applications in Visual Studio creating user controls or custom controls will often help you get a better application and decrease your development time. Often you will have problem using your user controls or custom controls in the Visual Studio designer. Forms using your controls will not show at all in the designer and sometimes Visual Studio will shut down because of this (happens often if you are referring to external .dll in the user control or custom control).
I will walk you through a simple example on how you can achieve this with out any problems at all.
I will use a simple example where I have created a Header user control that is referring to the Microsoft.WindowsMobile.dll and Microsoft.WindowsMobile.Status.dll. Then I have a simple Form that I will use the designer to append the Header to and make sure the Visual Studio designer still works.
I am using Visual Studio 2008, Windows Mobile 6 Professional SDK and .Net Compact Framework 3.5 for this example.