Special Keys
      The following key strokes perform a special action:
      F1Help
      <Enter>Duplicates an object when the edit field is empty (dup) 
      <Delete>Drops an object when the edit field is empty (drop) 
      \Swaps two objects when the edit field is empty (swap) 
      Ctrl+-Inserts negative sign (-), as opposed to performing the subtract command
      Ctrl+.Inserts degree symbol (°)
      Ctrl+AInserts Angstrom symbol (Å)
      Ctrl+EInserts Euro sign (€)
      Ctrl+UInserts micron symbol (µ)