docs: private Widget createUnzipCheckBox(final CmsFileInfo file) {
  
          final CmsToggleButton unzip = new CmsToggleButton();
          I_CmsUploadCss uploadCss = I_CmsLayoutBundle.INSTANCE.uploadCss();
          String caption = Messages.get().key(Messages.GUI_UNZIP_BUTTON_TEXT_0);
          unzip.setUpFace(caption, uploadCss.unzipButtonUpFace());
          unzip.setDownFace(caption, uploadCss.unzipButtonDownFace());
          unzip.addStyleName(uploadCss.unzipButton());
          unzip.addStyleName(org.opencms.gwt.client.ui.css.I_CmsLayoutBundle.INSTANCE.listItemWidgetCss().permaVisible());
          unzip.setDown(getFilesToUnzip(true).contains(file.getFileName()));
          if (!m_filesToUpload.containsKey(file.getFileName())) {
              unzip.disable(Messages.get().key(Messages.GUI_UPLOAD_FILE_NOT_SELECTED_0));
          }
          unzip.addClickHandler(new ClickHandler() {
  
              /**
               * @see com.google.gwt.event.dom.client.ClickHandler#onClick(com.google.gwt.event.dom.client.ClickEvent)
               */
              public void onClick(ClickEvent event) {
  
                  // add or remove the file from the list of files to upload
                  if (unzip.isDown()) {
                      CmsDebugLog.consoleLog("DOWN");
                      getFilesToUnzip(true).add(file.getFileName());
                  } else {
                      CmsDebugLog.consoleLog("UP");
                      getFilesToUnzip(true).remove(file.getFileName());
                  }
              }
          });
          return unzip;
      }