private void init() { initialized = true; setDefaultRenderer(Object.class, new DefaultOutlineCellRenderer()); ActionMap am = getActionMap(); //make rows expandable with left/rigt arrow keys Action a = am.get("selectNextColumn"); //NOI18N am.put("selectNextColumn", new ExpandAction(true, a)); //NOI18N a = am.get("selectPreviousColumn"); //NOI18N am.put("selectPreviousColumn", new ExpandAction(false, a)); //NOI18N }