JBTreeTable - how to set column width

Hi,

I'm trying to use JBTreeTable in the plugin that i'm trying to develop for intellij platform. I think i'm nearly there, but I cant figure out why the column is not rendered according to the preferred width that i set in the code.

Here is my snippet:

public class Sample {
    private JPanel contentPane;
    private JButton processButton;
    private JButton clearButton;
    private JTextArea fixMessageTextArea;
    private JPanel fixTreeContainer;


    private static class CustomNode extends DefaultMutableTreeNode {
        String name;
        Object value;

        CustomNode(String name, Object value) {
            this.name = name;
            this.value = value;
        }

        public Object getValue() {
            return value;
        }

        public String getName() {
            return name;
        }
    }

    public Sample() {
        ColumnInfo name = new ColumnInfo("Name") {
            @Nullable
            @Override
            public Object valueOf(Object o) {
                if (o instanceof CustomNode) {
                    return ((CustomNode) o).getName();
                } else {
                    return o;
                }
            }
        };

        ColumnInfo value = new ColumnInfo("Value") {
            @Nullable
            @Override
            public Object valueOf(Object o) {
                if (o instanceof CustomNode) {
                    return ((CustomNode) o).getValue();
                } else {
                    return o;
                }
            }
        };

        final ColumnInfo[] columns = {name, value};
        final ListTreeTableModel model = createTableModel(columns);
        final JBTreeTable treeTable = new JBTreeTable(model);

        treeTable.getTable().setAutoResizeMode(JBTable.AUTO_RESIZE_OFF);
        treeTable.getTable().getColumnModel().getColumn(0).setPreferredWidth(200); // width in pixels for column 1
        treeTable.getTable().getColumnModel().getColumn(1).setPreferredWidth(400); // width in pixels for column 1
        treeTable.getTree().setCellRenderer(new DefaultTreeCellRenderer());

        fixTreeContainer.add(treeTable,
                new GridConstraints(0, 0, 1, 1,
                        GridConstraints.ANCHOR_CENTER,
                        GridConstraints.FILL_BOTH, GridConstraints.SIZEPOLICY_WANT_GROW,
                        GridConstraints.SIZEPOLICY_WANT_GROW, null, new Dimension(150, 50),
                        null, 0, false));
    }

    @NotNull
    private static ListTreeTableModel createTableModel(ColumnInfo[] columns) {
        DefaultMutableTreeNode root = new DefaultMutableTreeNode();
        ListTreeTableModel model = new ListTreeTableModel(root, columns);
        DefaultMutableTreeNode first = new CustomNode("I am first name", "I am first value");
        DefaultMutableTreeNode second = new CustomNode("I am second name", "I am second value");
        root.add(first);
        root.add(second);
        DefaultMutableTreeNode child1 = new CustomNode("I am child namel", "I am child value");
        DefaultMutableTreeNode child2 = new CustomNode("I am child name2", "I am child value");
        DefaultMutableTreeNode child3 = new CustomNode("I am child name3", "I am child value");
        second.add(child1);
        second.add(child2);
        second.add(child3);
        return model;
    }

    public JPanel getContentPane() {
        return contentPane;
    }

and then in my code for the plugin:

public class FixParserToolWindowFactory implements ToolWindowFactory, DumbAware {

    @Override
    public void createToolWindowContent(@NotNull Project project, @NotNull ToolWindow toolWindow) {
        final FixParserWindowContent windowContent = new FixParserWindowContent(toolWindow);
        final Content content = ContentFactory.getInstance().createContent(windowContent.getContentPanel(), "", false);
        toolWindow.getContentManager().addContent(content);
    }

        public FixParserWindowContent(ToolWindow toolWindow) {
            contentPanel.setLayout(new BorderLayout(0, 20));
            contentPanel.setBorder(BorderFactory.createEmptyBorder(40, 0, 0, 0));
            contentPanel.add(new Sample().getContentPane(), BorderLayout.CENTER);
   
        }
  ...
  }      

with the code above, it looks like this:

Have i missed anything obvious? Also, is there a documentation on these widgets ? E.g. when i first started writing the plugin, I was using TreeTable (as opposed to JBTreeTable), and I couldnt figure out why the expand/collapse icon wasnt showing! Maybe a sample demo code in the jetbrains repo that shows how these components can be used?

Also, what do people usually use to develop the UI? for the above, i use the UI designer plugin in intellij, but it doesnt recognise all these widgets from Jetbrains. 

Thank you!