<oScrollBar>:display() --> self

        display() is a method of the ScrollBar class that is used for showing
        a scroll bar including its thumb on the screen.  display() uses the
        values of the following instance variables to correctly show the
        scroll bar in its current context, in addition to providing maximum
        flexibility in the manner a scroll bar appears on the screen:
        colorSpec, end, offset, orient, start, style, and thumbPos.