I recently made a design change in which I had moved most of the controls on a form into a  SF TabControl. Now I keep getting this design error. I searched and found a workaround to show the form designer, in which I close the form, clean the solution, then rebuild, and reopen; but it only works until I execute the app. Then it reverts back to the same designer error. Does anyone have any thoughts of how I can fix this?

This is a common problem in .NET.  This will not be the last time you will see this problem.  It is most prevalent when using a tab control and how the .NET designer loads the controls.  When you run your application, the designer thinks that it needs to reload the designer dialog....and then the problem occurs.  There is an issue with multi-page objects and the designer depending upon what is on the subsequent pages.  This is an issue with the .NET designer and there really isn't anything you can do....other than close the designer form and go back in.

FYI....this is more prevenlant in VB.NET than C# due to the nature of the compiler running in the back ground....but is does still happen in C#.

Ok, thanks for the help.

Sure...sorry I couldn't give you the "preferred" answer on this one.