One of the coolest feature of SharePoint Designer 2010 is the ability to check the user currently who logged in and to switch to a different user whenever you need to.
Remember the old SharePoint 2007 where you need to first login to the site, and then only you can open it using SharePoint Designer. Let say, you might be logged in with an administrator account. If you wanted to test something as a different user, how would you do that? Yeah, you’ll need to close the site and browser, login using different username via browser and open the site using SharePoint Designer 2007. Mmmmm… well, with SharePoint 2010 you don’t need to do that anymore!
To check the current user currently logged in, with open SharePoint Designer 2007, if you look in the bottom-left corner, you’ll see a tiny little person icon, as shown below:
Hovering over the icon with your mouse shows the name of the user currently logged in.
Clicking the icon allows you to log in with a different account.