On the Actions menu, the Copy 
command copies the selected files and folders from one side of the Folder Viewer to the other, overwriting any existing files on the target side.
If a folder is selected, only its filtered contents will be copied (same as if the folder was expanded and all visible contents selected). However, if an open folder is selected and any of its children are selected as well, then the folder's selection is ignored and only the selected children will be copied.
By default, a confirmation dialog appears before the copy. To skip the confirmation, open the Tools menu, click Options
, go to the Folder Views > Confirmations page, and disable Confirm file copy.