How do I switch between "Source", "Preview" and "Source and preview" tabs in Eclipse

I have to switch between "Source" and "Preview" tabs a lot while editing xml files in Eclipse. So trying to find a way to do this quickly without leaving the keyboard. Does anybody know of any? I am talking two, max three, key stroke long shortcuts. Well, I guess there should be a way to customize the key combinations. TIA

Solution

Check Preferences Dialog > General > Keys and find Previous/Next Sub-Tab command.

If you are in Windows, it is bound to Alt+PageUp and Alt+PageDown.

In MacOSX(Mac Book Air), it is bound to fn+alt+Arrow up and fn+alt+Arrow down.