Test case objects (and all their child objects) can also be cloned by dragging and dropping them within the same test case tree or to a different test case tree.

Cloning within the same test case

Test case objects can be cloned similarly to how they are repositioned as described here.  Select one or more test case nodes to be cloned. The test case nodes must be siblings (have the same parent node). Then, hold the Ctrl key 

Cloning to a different test case

Test case objects can be cloned to different test cases.