Pack Icons

  If you store your icons in an icon box, as you close windows
  your icon box develops gaps where the icons used to be.  To
  rearrange the icons in the Icon Box to fill in these gaps,
  choose Pack Icons from the Workspace Menu.

  If you have free-floating icons and choose Pack Icons from
  the Workspace Menu, the packed icons will be placed
  according to your default placement specified in the Icon

  Options dialog box.

  Packing icons together on the screen may help you to locate
  icons that are obscured by windows.