Duplicate window across monitors

I have a notebook with a projector attached. Normally I would set my the desktop to extend to the projector screen in Window's settings. I'm required to type something which should be seen by the audience. The projection is behind me so it's a bit tedious to type without seeing actually what I type.

All other windows should not be duplicated therefore the "duplicate the screen" option is not an option for me.

Is there any kind of software available with duplicates the window so I could put one of them on the projector screen?

UltraMon will do exactly what you want with its mirroring feature. It's available for for Windows 8, 7, Vista and XP.

For any OS X users that might stumble upon this, there's DuplicateWindows.