The command adds a copy of each selected layer to the image. The name of each new layer is the same as the name of the original layer, but with “copy” or a number appended to it.
Note that if there are any parasites attached to the selected layers, they are not duplicated.
You can access this command
From the main menu through → .
By using the keyboard shortcut Shift+Ctrl+D.
          From the
          Layers Dialog, you
          can access it through the 
          command of its context menu, or by clicking on the
          
            
          
          icon button on the bottom of that dialog.