Menu: Tools -> Options -> Projects and Solutions –> General
Versions: 2005,2008, 2010
Note: Several people have asked if you can turn this feature on and off at will. You can if you bind the View.TrackActivityinSolutionExplorer command to a keyboard shortcut.
By default, VS2010 will track the current file you are editing in Solution Explorer. It looks like this:
Notice that the current file being edited is also selected in Solution Explorer automatically. This is a great way to keep track of where you are in the solution when you are working with a lot of files. You can turn it off if you want. Just go to Tools -> Options -> Projects and Solutions -> General -> "Track Active Item in Solution Explorer" and uncheck the option to turn this feature off.