问ScrolledComposite不按鼠标滚动

EN

    scrolledComposite.addListener(SWT.MouseWheel, new Listener() {
        public void handleEvent(Event event) {
            System.out.println("MOUSE WHEEL");
            int wheelCount = event.count;
            wheelCount = (int) Math.ceil(wheelCount / 3.0f);
            while (wheelCount < 0) {
                scrolledComposite.getVerticalBar().setIncrement(4);
                wheelCount++;
            }

            while (wheelCount > 0) {
                scrolledComposite.getVerticalBar().setIncrement(-4);
                wheelCount--;
            }
        }
    });

    final ScrolledComposite scrolledComposite = new ScrolledComposite(mainComposite, SWT.BORDER | SWT.H_SCROLL | SWT.V_SCROLL);
    scrolledComposite.setExpandHorizontal(true);
    scrolledComposite.setExpandVertical(true);
    scrolledComposite.setBackground(SWTResourceManager.getColor(SWT.COLOR_MAGENTA));

    final Composite listComposite = new Composite(scrolledComposite, SWT.NONE);
    GridLayout layout = new GridLayout();
    layout.numColumns = 1;
    listComposite.setLayout(layout);

    final Composite composite_3 = new Composite(listComposite, SWT.NONE);
    GridLayout gridLayout = new GridLayout();
    gridLayout.numColumns = 8;
    composite_3.setLayout(gridLayout);

    scrolledComposite.setContent(listComposite);
    scrolledComposite.setMinSize(listComposite.computeSize(SWT.DEFAULT,SWT.DEFAULT));

    shell = new Shell();
    shell.setSize(450, 300);
    shell.setText("SWT Application");
    shell.setLayout(new FormLayout());

    Composite composite = new Composite(shell, SWT.NONE);
    composite.setBackground(SWTResourceManager.getColor(SWT.COLOR_YELLOW));
    FormData fd_composite = new FormData();
    fd_composite.bottom = new FormAttachment(0, 46);
    fd_composite.right = new FormAttachment(100);
    fd_composite.top = new FormAttachment(0);
    fd_composite.left = new FormAttachment(0);
    composite.setLayoutData(fd_composite);
    composite.setLayout(new FillLayout(SWT.HORIZONTAL));

    Composite composite_1 = new Composite(shell, SWT.NONE);
    FormData fd_composite_1 = new FormData();
    fd_composite_1.right = new FormAttachment(0, 100);
    fd_composite_1.top = new FormAttachment(composite, 1);
    fd_composite_1.left = new FormAttachment(0);
    fd_composite_1.bottom = new FormAttachment(100);
    composite_1.setLayoutData(fd_composite_1);

    Composite composite_2 = new Composite(shell, SWT.NONE);
    composite_2.setLayout(new FillLayout(SWT.HORIZONTAL));
    FormData fd_composite_2 = new FormData();
    fd_composite_2.top = new FormAttachment(composite, 1);
    fd_composite_2.left = new FormAttachment(composite_1, 1);
    fd_composite_2.bottom = new FormAttachment(100);
    fd_composite_2.right = new FormAttachment(100);
    composite_2.setLayoutData(fd_composite_2);

    ScrolledComposite scrolledComposite = new ScrolledComposite(composite_2, SWT.BORDER | SWT.H_SCROLL | SWT.V_SCROLL);
    scrolledComposite.setBackground(SWTResourceManager.getColor(SWT.COLOR_DARK_RED));
    scrolledComposite.setExpandHorizontal(true);
    scrolledComposite.setExpandVertical(true);

    Composite composite_3 = new Composite(scrolledComposite, SWT.NONE);
    composite_3.setLayout(new GridLayout(1, false));

    Composite composite_4 = new Composite(composite_3, SWT.NONE);
    composite_4.setBackground(SWTResourceManager.getColor(SWT.COLOR_BLUE));

    Composite composite_5 = new Composite(composite_3, SWT.NONE);
    composite_5.setBackground(SWTResourceManager.getColor(SWT.COLOR_MAGENTA));

    Composite composite_7 = new Composite(composite_3, SWT.NONE);
    composite_7.setBackground(SWTResourceManager.getColor(SWT.COLOR_DARK_BLUE));

    Composite composite_6 = new Composite(composite_3, SWT.NONE);
    scrolledComposite.setContent(composite_3);
    scrolledComposite.setMinSize(composite_3.computeSize(SWT.DEFAULT, SWT.DEFAULT));