Problem: When debugging a Silverlight 2.0 application, the breakpoint appears as an empty circle with a tooltip saying, "The breakpoint will not currently be hit. No symbols have been loaded for this document." See screen shot below.
Solution (at least for me): I had two different versions of the application in my ClientBin folder, and my aspx markup was pointing toward the older version. The source code opened in Visual Studio did not match the IL in the older *.xap. Update the source attribute of the <asp:Silverlight /> tag in your aspx markup to point toward the newest *.xap (and probably delete the old *.xap) and debugging should work again.
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