There is another solution for using it here:
http://www.codeproject.com/KB/aspnet/PageTags.aspx
But I don't want to add anything that intrusive to the software just to support master pages, especially since I really haven't gotten any requests from customers to add them (except yours). Our includes system works much simpler and easier, and doesn't require such extensive changes to the page directive.
Can I ask you why you want to use master pages so badly?
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