Then go vote on this bug report. Right now, in Visual Studio 2005, you can easily create a chain of hierarchical masters (child->master->master). This works great, however you cannot edit the child page in the designer in this situation. You can only edit the child page if there is only one level of master above it.

It should be obvious that anything beyond the simplest of website applications will need more than one level of master page linking. But as it stands now, we won't be able to edit the pages in the WYSIWYG editor... all html will have to be edited by hand.

Michael proposes that they not even try to show the master/master/etc content around the child container (like they do in the simple scenario that works). He is simply asking that they allow us to edit the child page in the designer - even if the inherited masterpage content is not visible.

So go vote on that bug!