code: public static CmsPopup showFrameDialog(
          String title,
          String dialogUri,
          Map<String, String> parameters,
          CloseHandler<PopupPanel> closeHandler) {
  
          CmsPopup popup = new CmsPopup(title);
          popup.removePadding();
          popup.addStyleName(I_CmsLayoutBundle.INSTANCE.contentEditorCss().contentEditor());
          popup.setGlassEnabled(true);
          CmsIFrame editorFrame = new CmsIFrame(IFRAME_NAME, "");
          popup.add(editorFrame);
          final FormElement formElement = CmsDomUtil.generateHiddenForm(dialogUri, Method.post, IFRAME_NAME, parameters);
          RootPanel.getBodyElement().appendChild(formElement);
          exportDialogFunctions(popup);
          popup.addCloseHandler(new CloseHandler<PopupPanel>() {
  
              public void onClose(CloseEvent<PopupPanel> event) {
  
                  formElement.removeFromParent();
                  removeExportedFunctions();
              }
          });
          if (closeHandler != null) {
              popup.addCloseHandler(closeHandler);
          }
          popup.center();
          formElement.submit();
          return popup;
      }
docs: Shows an iFrame dialog popup.<p>
  
  @param title the dialog title
  @param dialogUri the dialog URI
  @param parameters the dialog post parameters
  @param closeHandler the dialog close handler
  
  @return the opened popup