Windows - screen-shot of Alt-Tab context switcher

I was trying to take the screen shot of the Widows Task Switcher (Alt-Tab) using Windows 'PrtSc' (Print Screen Key) .
But no luck. The time I press the 'PrtSc' key, alt tab 'Widows Task Switcher' vanishes.

Any idea how I can perform this using Window's PrtSc' ? Any tip/help will be really appreciated.

** The above snap was taken using Freez Screen Video Capture tool.