I "enhanced" a program and screwed up something. As always, I had made a backup under a different name. Now I'm in Microsoft Visual Studio, navigating back and forth between the original code and the enhanced code, so that I can find my boo-boo. I'm clicking first on the tab for one program, then on the tab for the other. But that is slow and awkward. Is there a keyboard shortcut where I can quickly flip back and forth?