TreeTable Border

TreeTable border Only part of it is shown

how to set value border

class Renderer extends ColoredTreeCellRenderer {
    @Override
    public void customizeCellRenderer(@NotNull JTree tree, Object value, boolean selected, boolean expanded, boolean leaf, int row, boolean hasFocus) {
        CustomNode node = (CustomNode) value;
        setBorder(BorderFactory.createLineBorder(JBColor.BLACK, 3));
        append(node.getKey());
    }
}