When working with an ASP.NET application in Visual Studio 2008, my errors window often contains a list of errors such as;
The name 'txtUsername' does not exists in the current context.
When I double click on the error, it will go to the source, show the control underlined in red, then realise it's mistake and remove those errors. It's a real pain because if you have a genuine error, you have go and hunt for it.