no scrolling display selected or missing display name

    Facility: DEBUG, VMS Debugger

    Explanation: The user did not enter a display name with the
    command, and the debugger attempted to use the display with the
    SCROLL attribute. However, no display currently has the SCROLL
    attribute.

    User Action: Either reenter the command, specifying a display
    name, or SELECT a display to have the SCROLL attribute and
    reenter the command.