This was driving me crazy but got it going:
Just to clarify : on Mac the "alt" key is better known as the "OPTION" key. My keyboard shows "OPTION" readily, as well as "alt" in tiny little letters - hard to see.
Press and hold down the "OPTION" key and while holding this, mouse click and hold whilst dragging loop to copy.... release mouse and key when copied. Drag loop(s) to snap to beat one (or anywhere within) of your desired bar.
You can also select multiple adjacent loops for copying by highlighting them and doing above procedure.
Cheers,
Dave
