Library /sys$common/syshlp/pca$help.hlb SET, DISPLAY, Description  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    The SET DISPLAY command creates new screen displays so that more
    displays than the default PLOT, OUT, SRC and PROMPT displays
    may appear on your terminal screen. By defining multiple plot
    displays and selecting each one in turn as the current plot
    display, you can simultaneously display several different
    histograms or tables on the screen. Similarly, you can create
    multiple output displays.