debugging design mode, user controls, custom controls
To debug control design mode (errors occurring when using the design environment), use a second instance of Visual Studio .NET on the same machine.
Start a second Visual Studio .NET, open the same solution you are debugging.
In the original instance (#1), Debug->Processes, select “devenv” process, click Attach. Leave at least “Common Language Runtime” checked. Click OK. Close.
Set appropriate breakpoints in the source files in #1 and/or enable breaking into the debugger on exceptions in #1.
In the second instance (#2), exercise the designer to trigger the error case.