Library /sys$common/syshlp/lse$menu.hlb SET_BALANCE_WINDOWS  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Syntax:  SET BALANCE WINDOWS boolean

  Automatically balances window length whenever you change the number
  of windows.

  The parameter value off disables window balancing and allows windows
  to have unequal lengths.