CSS editor in Visual Studio 2011 introduced many new features for web developers and it helps developers to work with CSS more efficiently and organize way. I talked about such two features over here http://abhijan.me/yCL4LH and http://abhijan.me/zvnmqu . CSS editor has another enhancement, which is “supporting direct code comment and uncomment”.
Prior to Visual Studio 2011, you have had to comment out CSS by manually typing /* and */ for code block. But in Visual Studio 2011 you will find comment and uncomment button enable in tool bar as shown in below.
You can also use standard shortcut key ( CTRL + K + C ) for commenting out the code block and (CTRL + K + U ) for uncommenting the code block.
Hope this helps !