I ran into a positive spin of that same feature/bug a few months ago when I loaded two instances of VS.NET 2003, each of them loaded a different solution/project. Then I ran both solutions: one was a Windows Form client app and the other a web service references by the Windows Form app.

As I was stepping throught the code in the Windows Form app, the IDE loaded the code of the web service in my Windows Form debug session, it jumped the web service's code and let me continue debugging it. Kind of crazy but handy.

It took me a while to figure out how to repeat that behavior (since it is a little bit tricky) and I actually have the notes on how to do it at the bottom of this page:

http://hcorrea.no-ip.com/dotwiki/Default.aspx?topic=WebServiceTips




>I have version 1.0 and 1.1 of Visual Studio Net loaded on my development machine. I was in version 1.1 and pressed F5 to run an application that I am testing. Then I went to version 1.0 and did the same thing to compare a specific behavior of a similar application. The following error was thrown at that time:
>
>Error while trying to run project: Unable to start debugging on web server. A debugger is already attached. Would you like to disable future attempts to debug ASP.NET pages for this project?
>
>That word "future" bothered me - like in forever or never again?
>
>Ouch! Live and learn. Yes, versions 1.0 and 1.1 can reside on the same machine but do not do what I did – it does not work. Or it does work but perhaps not the way you would like.
>
>Now who would ever want to do something like this? I guess I am the only one. Not a big deal but a pain it is! :)
>
>Tom