With advanced samples of MPlatform SDK or with Sample File Playback C# (or VB.Net) in Visual Studio, sometimes you can see this instead of a proper design view:
To solve the problem, you should do the following:
- Close the Design view of the form
- Change a build configuration from x64 to x86
- Clean and rebuild the solution
- Open the design view again
As a result, you should see a proper design view of your app: