Only one instance of a ScriptManager can be added to the page

Question

I am getting a bizarre error:

Only one instance of a ScriptManager can be added to the page.

When I found this bug originally, I noticed that I had a "ScriptManager" tag in one of my pages and an ajax:ToolScriptManager in the masterpage of that same page. So I commented out the "ScriptManager" tag with server comments (<% %>) and uploaded to the live site. Still got the error. I tried deleting the line entirely and still the error occurs.

Interestingly enough, the error is not happening on my local copy running without debug mode.

Any clues to what's going on? I'm pretty sure I'm using ASP.NET 3.5 and it's a web app not a web site. Do I need to compile or something before changes take effect?

Answer 1

The problem was I was uploading to one code base and testing on a different code base(on a different server). So the changes I was making were having no effect. Whoops!