The EXPAND command moves one or more display-window borders
    according to the qualifiers specified (/UP[:n], /DOWN[:n],
    RIGHT[:n], /LEFT[:n]).

    The EXPAND command does not affect the order of a display on
    the display pasteboard. Depending on the relative order of
    displays, the EXPAND command may cause the specified display to
    hide or uncover another display or be hidden by another display,
    partially or totally.

    Except for the PROMPT display, any display can be contracted to
    the point where it disappears (at which point it is marked as
    "removed"). It can then be expanded from that point. Contracting
    a display to the point where it disappears will cause it to
    lose any attributes that were selected for it. The PROMPT
    display cannot be contracted or expanded horizontally but can
    be contracted vertically to a height of two lines.

    A window border can be expanded only up to the edge of the
    screen. The left and top window borders cannot be expanded beyond
    the left and top edges of the display, respectively. The right
    border can be expanded up to 255 columns from the left display
    edge. The bottom border of a display can be expanded down only to
    the bottom edge of the plot's summary page display (to the end of
    the source module).

    You must specify at least one qualifier.