Visual Studio environment layout settings

While working in Visual Studio yesterday I accidentally hid the tabs that show the open files, and couldnt figure out how I did that or how to reverse it. With a bit of looking around in the Visual Studio menus (after failing to find an answer in google) it turns out that I changed the environment settings from Tabbed to MDI.

To get this back to what it was the solution is, go to Tools->Options, click on Environment then General and select the tabbed option.