Duplicate System.Web.UI.AsyncPostBackTrigger Controls keep getting inserted automatically, causing Parser Errors

Question

I have an update panel with a number of [asp:AsyncPostBackTrigger...] controls, and everything was working fine. But now, something keeps inserting duplicate AsyncTriggers, and instead of simply being [asp:AsyncPostBackTrigger...] controls they're [System.Web.UI.AsyncPostBackTrigger...] controls, and I get parser errors as a result.

So I delete the duplicate triggers, and they get re-inserted within a few minutes, seemingly randomly.

Anyone know whats going on here?

Answer 1

Think I found the answer here:

http://stackoverflow.com/questions/1062955/why-does-visual-studio-2008-break-my-web-page