Clicking a New Menu attribute looks like it locks up Pathfinder Office
It's not really locked up. The window is just out of view of the user. Same thing can happen with Data Transfer.
If you lose a window like that out of Pathfinder Office in the future, remember this little trick:
Hold down Alt + the space bar,and then hit M on your keyboard. Then push and hold either the left or right arrow on your keyboard, and it should pull it back onto the screen where you expect it to be.