You can work with spreadsheets, specifications, flowcharts, and other Active documents without leaving the development environment. When you are working with these documents in Developer Studio, the toolbars of the associated COM component are available and work normally. (Microsoft Word and Microsoft Excel are examples of COM components.)
If you create a file by using software other than Visual C++ and COM components, you can still add the file to your project. You can also open the file from the FileView pane, but the associated application is started in a separate window.