code: private void mkdir(IStructuredSelection selection) {
      List<DFSFolder> folders = filterSelection(DFSFolder.class, selection);
      if (folders.size() >= 1) {
        DFSFolder folder = folders.get(0);
        InputDialog dialog =
            new InputDialog(Display.getCurrent().getActiveShell(),
                "Create subfolder", "Enter the name of the subfolder", "",
                null);
        if (dialog.open() == InputDialog.OK)
          folder.mkdir(dialog.getValue());
      }
    }
docs: Create a new sub-folder into an existing directory
  
  @param selection