category.add(defaultMutableTreeNode);
defaultMutableTreeNode = new DefaultMutableTreeNode(new ChartInfo("BarChart06 - Histogram Overlapped", new BarChart06().getChart()));
category.add(defaultMutableTreeNode);
defaultMutableTreeNode = new DefaultMutableTreeNode(new ChartInfo("BarChart07 - Histogram Not Overlapped", new BarChart07().getChart()));
category.add(defaultMutableTreeNode);
// Theme category
category = new DefaultMutableTreeNode("Chart Themes");
top.add(category);