code: public CmsFileInput createFileInput() {
  
          // remove the current file input field and add a new one
          CmsFileInput previous = m_fileInput;
          if (m_fileInput != null) {
              m_fileInput.getElement().getStyle().setDisplay(Display.NONE);
          }
          m_fileInput = new CmsFileInput();
          m_fileInput.addChangeHandler(new ChangeHandler() {
  
              public void onChange(ChangeEvent event) {
  
                  CmsDomUtil.ensureMouseOut(m_main.getElement());
                  m_buttonHandler.onChange(m_fileInput);
              }
          });
          m_buttonHandler.initializeFileInput(m_fileInput);
          m_main.add(m_fileInput);
          return previous;
      }
docs: Creates and adds a file input.<p>
  
  @return returns the previous file input widget