By default AutoCAD allows you to select multiple objects. Some time while selecting objects the first selection or previously selected objects are removed from the selection set, the users are very much annoyed by this behavior.
The solution is “PICKADD” system variable.
Type in command line < pickadd > and set value = 1


  • Turns off PICKADD. The objects most recently selected become the selection set. Previously     selected objects are automatically removed from the selection set.
  • Turns on PICKADD. Each object selected, either individually or by windowing, is added to       the current selection set.
  • 2Turns on PICKADD. Each object selected, either individually or by windowing, is added to        the current selection set. If the SELECT command is used, keeps objects selected after the command ends.