I always used keyboard commands to quickly switch between windows in Corel Draw. It was always Ctrl-W then the window number. In 2017, there's no more window number. I've been working this way for over 15 years! Why did Corel decide to take that functionality away from us?
Ctrl+Tab Switches windows. Ctrl+W is refresh screen, it has been forever.
I would guess that DaveS is thinking of Alt+W, which takes one to the "Window" menu. In X5, it looks like this:
The "1", "2", and "3" in front of the document names are the numbers that one could press to switch directly to an open document.