Opening a Folder in a New Window

  Choose Open Folder In New Window from the File menu's
  Open-Close submenu to open the first selected folder in a
  new main window.  The messages in the open folder are listed
  below the folder name in the new main window.

  You can perform all Mail tasks on the drawers, folders, and
  messages displayed in the new window.

  Additional topics:

  *   Overview of Mail