Background compilation is a feature of the Visual Studio IDE whereby code is compiled as it is written by the programmer with the purpose of identifying compilation errors without requiring the solution to be built. This feature has been available for Visual Basic since .NET 1.1 and was present in early versions of Visual Studio for Visual Basic .NET. However, background compilation is a relatively new concept for Visual C# and is available with service pack 1 for Visual Studio 2008 Standard Edition and above. A distinct disadvantage for C# is that the Error List panel does not update until the solution is rebuilt. Refactoring large projects in C# is made more difficult by the need to frequently rebuild the solution in order to highlight compilation errors. Such is not the case with Visual Basic because the Error List panel is synchronized with the background compiler.