ASP.NET Theme ignored

[Apope56]

Does anyone know why dotnet would ignore themes on a particular
website?

I created a dummy website and added themes to it and it worked OK, but
when I try to theme my existing site, the theme is ignored. (No css
links are even created in the HTML markup.)

Yet the site compiles fine.

I'm assuming that something I'm doing is conflicting somehow with
themes, but I'll be damned if I can figure out what it is.

Any ideas? What conflicts with themes?

 

[Apope56]

Does anyone know why dotnet would ignore themes on a particular
website?

I created a dummy website and added themes to it and it worked OK, but
when I try to theme my existing site, the theme is ignored. (No css
links are even created in the HTML markup.)

Yet the site compiles fine.

I'm assuming that something I'm doing is conflicting somehow with
themes, but I'll be damned if I can figure out what it is.

Any ideas? What conflicts with themes?

I found my problem.
In global.asax I had this left over from a prior project:

void Application_Start(object sender, EventArgs e)
{
// Code that runs on application startup
MyVirtualPathProvider myVpp = new MyVirtualPathProvider();

System.Web.Hosting.HostingEnvironment.RegisterVirtualPathProvider(myVpp);
}

The virtual path provider messed with the path to the Theme so it
wasn't found.