Have you seen my answers in your other thread?
http://forum.thegamecreators.com/?m=forum_view&t=175418&b=22
I can only imagine the following alternatives:
1. You use Windows API to create the user interface. If you want drag-and-drop visual dialog editing, you need to use an external one because Visual Studio Express does not come with a resource editor, but it can compile dialog resources for you if you provide the file. I am using
http://www.resedit.net/. However, you need to learn about the Windows API dialog callback functions to make those dialog boxes work.
2. You switch to the .NET version of Dark GDK and then you can use Windows Forms. However, the .NET version is not free and I don't know if it's updated regularly or not. Besides, the .NET framework must be present on the user's machine and that's one more thing to worry about when deploying your application.
(I have even seen on the forum a .NET wrapper for Dark GDK made by Diggsey, who managed to integrate the two by making the whole program a DLL. It doesn't sound convenient at all but might work.)
3. You leave the Windows interface entirely and use something which draws interface elements onto the DirectX surface using either DirectX or Dark GDK drawing commands or sprites. Have a look in the other thread what I recommended there: Dark Forms and MAUI. Although they are not drag-and-drop but should be easy to use and test.
I don't know the scope and needs of your application but if you want the most painless way, I would recommend the third alternative as a start.