Sometimes I get the message "Exception of type 'System.ComponentModel.Design.ExceptionCollection' was thrown" When trying to open a Form in designer view.
The real problem of the "ExceptionCollection" being thrown is that when there is a WSOD (White Screen of Darn) indicating a designer load issue, the designer gets unloaded. These get caught by the unload method and get displayed in the dialog box you see.
So, to fix this you should:
* Attach a visual studio debugger to VS. Turn on exception catching when first thrown (in the Debug|Exceptions menu).
* Open the designer with the debugger attached
* Determine what component is throwing the exception.
Sometimes you cannot open the form design view because of a missing resource file or an invalid reference in the design code unit
