Customize the Visual Studio Editor using the VS SDK. You can use editor extensions to customize the appearance and behavior of the Visual Studio. The following are some of the ways in which you can extend Visual Studio:

• Add commands, buttons, menus, and other UI elements to the IDE
• Add tool windows for new functionality
• Extend IntelliSense for a given language, or provide IntelliSense for new programming languages
• Use light bulbs to provide hints and suggestions that help developers write better code
• Enable support for a new language
• Add a custom project type
• Reach millions of developers via the Visual Studio Gallery

If you’ve never written a Visual Studio extension before, you should find more information about these features at Starting to Develop Visual Studio Extensions.