code: protected void openDialog(I_CmsGalleryConfiguration configuration) {
  
          Document.get().getBody().addClassName(I_CmsButton.ButtonData.WAND_BUTTON.getIconClass());
          if (m_dialog == null) {
              SimplePanel tabsContainer = new SimplePanel();
              tabsContainer.addStyleName(I_CmsLayoutBundle.INSTANCE.containerpageCss().menuTabContainer());
              int dialogHeight = CmsToolbarPopup.getAvailableHeight();
              int dialogWidth = CmsToolbarPopup.getAvailableWidth();
              m_dialog = createDialog(configuration, new I_CmsGalleryHandler() {
  
                  public boolean filterDnd(CmsResultItemBean resultBean) {
  
                      return CmsGwtConstants.TYPE_IMAGE.equals(resultBean.getType());
                  }
  
                  public Widget getAdditionalTypeTabControl() {
  
                      return null;
                  }
  
                  public I_CmsAutoHider getAutoHideParent() {
  
                      return getPopup();
                  }
  
                  public CmsDNDHandler getDndHandler() {
  
                      return CmsContainerpageController.get().getDndHandler();
                  }
  
                  public void processResultItem(CmsResultListItem item) {
  
                      item.setData(DND_MARKER);
                      item.setDndHelperClass("imagedrag");
                      item.setDndParentClass(
                          "imageparent "
                              + org.opencms.ade.galleries.client.ui.css.I_CmsLayoutBundle.INSTANCE.galleryResultItemCss().tilingList());
                      //item.setDragHelperTransformer(DRAG_HELPER_TRANSFORMER);
                  }
  
              });
              m_dialog.setDialogSize(dialogWidth, dialogHeight);
              getPopup().setWidth(dialogWidth);
              tabsContainer.add(m_dialog);
              m_contentPanel.add(tabsContainer);
          } else {
              int dialogWidth = CmsToolbarPopup.getAvailableWidth();
              getPopup().setWidth(dialogWidth);
              m_dialog.truncate("GALLERY_DIALOG_TM", dialogWidth);
              m_dialog.updateSizes();
          }
      }
docs: Opens the dialog given the loaded gallery configuration.<p>
  
  @param configuration the gallery configuration