Have you ever opened someone else’s source code (maybe an open source, code sample, or even other team mate) and the code just isn’t aligned? This can happen because of spaces and tabs. By default, Visual Studio shows a tab as four spaces. So without white space visible (Tricks #003) four spaces, looks the same as a tab. If a previous developer (who maybe wasn’t even using Visual Studio) had tabs setup differently.
This quick 50 second video, shows you how to instantly convert spaces to tabs, or tabs to spaces. Either way you like it, Visual Studio is there to make you happy.
[CTRL]+[R],[W] = Show / Hide White Space
Edit | Advanced | Tabify Selected Lines = Convert Spaces to Tabs
Edit | Advanced | Untabify Selected Lines = Convert Tabs to Spaces
http://scottcate.looplogic.com/vstricks019