Design-time support

I've got a class derived from System.Windows.Forms.Control. I've added some design-time support and would like to customize the appearence of the design surface (for example change its back color, or draw a custom grid). I understand one should implement the IRootDesigner interface, or derive a new class from, say DocumentDesigner, but I'm a bit lost and all my attempts to do so result in exceptions thrown at design time with ugly error messages such as "error loading the document...". If anyone knows how to implement this, any help would be welcome. thank you in advance

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