Why can not debug Silverlight ?
If you are building your Silverlight application, or combine a silverlight application with your ASP.NET web project, you might get a trouble: You found you could not debug Silverlight applications even you use Visual Studio 2010.
You searched many solutions from Google, and you might have tried all of them , but still did not work.
What the problem is really ? HaHa... my friend, maybe you are a super Firefox fans just like me, both of you and me don't want to try other browsers, actually the problem is not a problem, is just because we seldom use our another browser. My friend: just use your IE as your web project's browser, and see what will happen ?
Yes, now your silverlight can be debugged !!
About how to set IE as your web application's browser: Select any .aspx and right click mouse, select Browse with..., choose IE, and set as default. now done !