the process copies all elements from another window into the window you have currently selected.
A better name for it would be " Copy from other window into this window".
So the steps are:
1. create a new empty window
2. run the process "copy window" and select the window you want to copy everything from
3. create a new menu node for your new window
4. set permissions so you can see it using either "role access update" or adding the window manually to your role
enjoy your new window!