Element actions can be found at the top right of the sidebar.
Duplicating an element (⌘ + D) creates an exact copy, including nested elements, either below or next to the original.
Copy an element (⌘ + C) to save it to your clipboard. When pasting (⌘ + V), you will be able to select exactly where to place the copied element, similar to sorting.
You can delete any selected element by pressing delete/backspace.