public void add(final int index, final TabConfig tab) {
        if (tabs == null) {
            tabs = new ArrayList<>();
        }
        if (index >= tabs.size()) {
            tabs.add(tab);
        } else {
            tabs.add(index, tab);
        }
        tab.setParent(this);
    }
The preferred size of this layout in width, height.
stroom-core-shared/src/main/java/stroom/dashboard/shared/TabLayoutConfig.java