tt.addContainerProperty("Bar", String.class, "");
tt.setColumnWidth("Bar", 100);
tt.setIcon(icon);
tt.setHeight(400, PIXELS);
Object item1 = tt.addItem(new Object[] { "Foo", "Bar" }, null);
Object item2 = tt.addItem(new Object[] { "Foo2", "Bar2" }, null);
tt.setItemIcon(item1, icon);
tt.setItemIcon(item2, icon);
tt.setParent(item2, item1);