We're working on a new feature for a client web site that uses the asp:Wizard control wrapped in an UpdatePanel. Since ASP provides this nice Page.MaintainScrollPositionOnPostback method that automatically sets up JavaScript that will keep your page at approximately the same position after postbacks, I enabled it in Web.config and didn't think about it for a few days ... until we noticed that most of the dialog boxes in Sitecore had quit working. I could see via Firebug that the postbacks were happening when buttons were clicked that SHOULD have resulted in something happening, but the responses were empty, even though they were accompanied with a HTTP 200 response code.

After about 24 hours of head-scratching, and attempting to roll back other code changes, I realized I'd made that seemingly minor change to Web.config. I was tempted to dismiss it entirely since there wasn't any logical reason I could think of that the change would have affected Sitecore, but I went ahead and removed it and tested ... and whaddya know, things started working again. I'm at a loss to explain why it makes a difference since I'm not intimately familiar with the internals of Sitecore, but I'm tempted to start taking a look at things using ILSpy and see if I can figure out what the deal is.