public static int getColumnWidth(final int maxDepth) {
        if (maxDepth >= 0) {
            return (maxDepth * ICON_WIDTH) + ICON_WIDTH + PADDING;
        } else {
            return 0;
        }
    }
Get the maximum column width required to fit expander icons for all levels
stroom-core-client-widget/src/main/java/stroom/cell/expander/client/ExpanderCell.java