Why doesn't "Adding multiple instances of the same sheet" work as described?

I’m trying my first hierarchical schematic.

This FAQ suggests that another instance of a hierarchical sheet can "be added by simply duplicating an existing instance using either crtl+c followed by crtl+v on a block selection or right-click->duplicate block"

In actuality, this does not work. CTRL-C and CTRL-V do nothing to the existing instance. There is no duplicate sheet option on the right click menu for the existing sheet instance.

The only approach that works is creating a new hierarchical sheet, and manually editing the file name. Is this a bug specific to 5.1.6 on Windows?

Figured it out - it has to do with selection. The sheet has to be selected, not just right-clicked on the page, before the duplicate options available. CTRL-C works while selected - even though the sheet is moving, once CTRL-C is used, it returns to its starting location.