I've been following this problem with the ASP.NET designer for a little while, and I voted on the issue in LadyBug.

As an ASP.NET MVP and an ASPInsider I am mighty miffed about the decision not to fix this issue. The component designer is one of the most powerful features in Visual Studio and ASP.NET supporting it is diabolical.

I wonder what other ASP.NET MVPs and ASPInsiders think about this issue. I'd like to plead with the PMs on the web team to reconsider this decision. Surely the increased robustness that partial classes brings to designer serialisation address most of the issues - what could you learn from the Windows Forms team?