<i>The folder tree, aka file categories, is essential is file management.</i><b>文件夹树,又名文件类别,对文件管理至关重要。</b> <i>You can expand and collapse category levels to display hierarchical folders with their own files.</i><b>您可以展开和折叠类别级别,以显示具有其自身文件的分层文件夹。</b> <i>Sub-folder levels are unlimited.</i><b>子文件夹级别不受限制。</b> <i>Moreover, there is no faster way to edit category position and level that using drag'n drop.</i><b>此外,没有比使用拖放功能更快的方法来编辑类别位置和级别。</b>