Copy an Object Using the Model Explorer

You can copy an object in from the Model Explorer to the diagram. When you drag an object, the cursor indicates the action that you are performing. If the default action is not Copy, you can manually override the default to copy the object rather than move it by pressing CTRL while dragging.

To copy an object using the Model Explorer, select the object and use CTRL+drag to copy it to a new location.

More information:

How the Model Explorer Works

Sort Domains in the Model Explorer