private int getMinMarkerBarTop() {
        final int scrollBarTop = getScrollBarTop();

        int top = SUMMARY_CONTAINER_HEIGHT;
        top += 1;

        if (top < scrollBarTop) {
            return scrollBarTop;
        }

        return top;
    }
Redraws the overview bar. This is called when indicators are
added/removed, when indicators are set to be displayed and when the
widget is resized.
stroom-core-client-widget/src/main/java/stroom/editor/client/view/RightBar.java