防止Visual Studio自动创建“混合平台”解决方案配置

How do I prevent Visual Studio 2008 from automatically creating the "Mixed Platforms" and "Any CPU" solution configurations? We have "Win32" and "x64" configurations and a developer needs to choose between them. However, as soon as anyone makes any changes to the solution VS automatically creates "Mixed Platforms" and it seems to be the default configuration. This causes a lot of issues, because it turns out some new projects are not selected in this configuration or the wrong project configuration is selected, etc. I just want to stop it doing that and manage the solution configurations myself.How do I prevent Visual Studio 2008 from automa