Page is not responsed after a file is download

Hi, please see the following code:
   @Override
    protected void init(VaadinRequest request) {    
            final VerticalLayout layout = new VerticalLayout();
            layout.setMargin(true);
            setContent(layout);
        
        Button button = new Button("Download");        
        button.addClickListener(new ClickListener() {

            @Override
            public void buttonClick(ClickEvent event) {
                StreamResource.StreamSource source = new StreamResource.StreamSource() {

                    public InputStream getStream() {
                        byte b = null;
                        String ppp = "<table><tr><td><span>djfdlkfj</span></td></tr></table>";
                        b = ppp.getBytes();
                        return new ByteArrayInputStream(b);
                    }
                };

                String namefile = "picture.xls";
                StreamResource resource = new StreamResource(source, namefile);

                resource.getStream().setParameter("Content-Disposition", "attachment;filename=\"" + namefile + "\"");
                resource.setMIMEType("application/xls");
                resource.setCacheTime(0);
                
                Page.getCurrent().open(resource, "_self", true);
                
            }
            
        });
        
        layout.addComponent(button);
        
        Button dummy = new Button("Dummy");        
        dummy.addClickListener(new ClickListener() {

            @Override
            public void buttonClick(ClickEvent event) {
                Notification.show("Dummy button is clicked");
            }
        });
        layout.addComponent(dummy);
    }

1. Click button Download, file picture.xls is download.
2. Button Dummy and Download are not responsed any more.
3. Refresh browser, everything is normal.

Is there anything missed when using deprecated method Page.getCurrent().open(...) in Vaddin 7.7.6?

I'm not sure about the Page.open. I would recommend to use FileDownloader https://vaadin.com/api/7.7.6/com/vaadin/server/FileDownloader.html