A problem has been discovered in Visual Studio .NET that can cause data to be lost while switching views. Download the fix.
Visual Studio .NET contains a problem that can result in a loss of data when switching views in the WebForms designer.
Microsoft has corrected this issue with a downloadable patch. All customers who use Visual Studio .NET should download and apply this update.
When switching views in the WebForm designer, code or controls can disappear.
For additional information, please see Microsoft Knowledge Base article 324199.
Select to download this file to update Visual Studio .NET and eliminate this issue.