When trying to view the designer of a user control that inherits from another user control that contains any control the following error is displayed:
An error occurred while loading the document. Fix the error, and then try loading the document again.
I see this sometimes, what probablly goes wrong here how to avoid it
I have seen simillar error even when I had one user control.

Errors while viewing usercontrol's design mode
Bill Records
Your assumption is right, I use window Forms. I get warning window if project is not built to use the new control, I make some mistake and I overcome by creating a new file. I know not where I make this mistake and I do not have a screen shot to show now. Its alright, I will get this later if I come across.
Thanks,
Stanley
Stefan Hendricks
Are you talking about a Windows Forms User Control
Assuming so, this can happen if you are inheriting from a user control that has never been compiled. If you compile your project that contains the user control that you wish to inherit from first, you should have no problem inheriting from it and viewing it in the designer. In fact, if you would have used the 'Inherited User Control' Item type in visual studio it would have told you as much in a warning box.
Short answer: Build your project and it should work.
- David Sandor