Glassy Delphi

In Fun with enumerators, part 5 I wrote "Class helpers offer us a way to extend classes that we cannot touch otherwise. For example, they are used inside Delphi 2007's VCL to add glass support to TCustomForm (it was impossible to extend TCustomForm itself as D2007 is a non-breaking release)." For all interested - Hallvard just published nice description of how glass support was added to the TCustomForm.