Codigo Menu Arbol Eclipse.Swt.Swt (Swt.Widgets.Tree)

package x;

import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.layout.FormAttachment;
import org.eclipse.swt.layout.FormData;
importorg.eclipse.swt.layout.FormLayout;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.MenuItem;
importorg.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeItem;
import org.eclipse.wb.swt.SWTResourceManager;
import org.eclipse.swt.widgets.TreeColumn;/*-----*/

public class swtapp_x {
private Tree tree;

/**
* Launch the application.
* @param args
*/
public static void main(String[] args) {
try {
swtapp_x window = newswtapp_x();
window.open();
} catch (Exception e) {
e.printStackTrace();
}
}

/**
* Open the window.
*/
public void open() {
Display display = Display.getDefault();
ShellshlSwtApplicationPrueba = new Shell();
shlSwtApplicationPrueba.setSize(450, 300);
shlSwtApplicationPrueba.setText("SWT Application Prueba");
shlSwtApplicationPrueba.setLayout(new FormLayout());

Menu menu = newMenu(shlSwtApplicationPrueba, SWT.BAR);
shlSwtApplicationPrueba.setMenuBar(menu);

MenuItem mntmNewSubmenu = new MenuItem(menu, SWT.CASCADE);
mntmNewSubmenu.setText("New SubMenu");

Menumenu_1 = new Menu(mntmNewSubmenu);
mntmNewSubmenu.setMenu(menu_1);

MenuItem mntmNewItem = new MenuItem(menu_1, SWT.NONE);
mntmNewItem.setText("New Item1");

Canvas canvas = newCanvas(shlSwtApplicationPrueba, SWT.NONE);
canvas.setBackground(SWTResourceManager.getColor(SWT.COLOR_GREEN));
FormData fd_canvas = new FormData();
fd_canvas.top = new FormAttachment(0);
fd_canvas.left = newFormAttachment(0);
fd_canvas.bottom = new FormAttachment(0, 232);
fd_canvas.right = new FormAttachment(0, 336);
canvas.setLayoutData(fd_canvas);

tree = new Tree(canvas, SWT.BORDER);...