Update 18:23: Oh boy, Did I make a booboo!
You can disregard everything posted below. I made a stupid mistake and am very much ashamed. My .aspx, including the page directive below was missing the actual <%@ Page %> statement. Well, maybe this helps somebody overlooking the same thing, but I am truly sorry for wasting your time :-)
With Visual Studio 2008, the trouble with the nested masterpages not displaying in the IDE has been resolved, but it looks like we're not out of the woods yet. I don't really use the designer, but I today I wanted to check if nested masterpages really are supported, which apparently was like opening pandora's box.
I am running into two problems for which cannot find a fix anywhere on the web.
First off: The designer works great for masterpages. Opening a masterpage or nested masterpage in the Visual Studio 2008 designer works like a charm. Trouble start when you want to create pages based on these masterpages (who would want to do that?).
Problem 1: Custom declarative properties break the designer entirely
I am used to working with a common basepage for all my .aspx files, to add not only common functionality, but also common properties to set for each page. I use these properties declaritively, like so:
<%@
Language = "C#"
MasterPageFile = "~/includes/masterpages/Product.master"
Inherits = "LuaLayout.Common.BasePage"
EnableSessionState = "False"
EnableViewState = "False"
Title = "Lua 3 Column Layout"
Keywords = "Lua, Rocks, !"
MetaDescription = "This layout was created by Rinze Cats"
%>
Both keywords and metadescription are public properties defined in Common.BasePage. They work, but get the red underlining you really don't want to see. This I can most certainly live with. However, this completely disables design mode. It's just gives you an error that there's a problem with some controls on your page.
Problem 2:
This one is really getting to me. The designer appears to cache certain page settings which it will not release, not even when restarting the entire development environment. For example, changing the masterpage in the above MasterPageFile Directive does not change anything in the designer. It simply does not get updated. It's driving me completely mad. Because of this, I cannot test any further.
Has anybody experienced these problems? I think the first one just might not be supported (which would be very disappointing), the second one looks like a serious bug to me, but all I know is that it's not working. Any help/fixes are greatly appreciated. My VS 2008 build is: 9.0.30729.1 SP. I have looked into the 'Path' problem you read about when searching for designer issues on google, but this is not fixing anything for me.