code: @Override
      protected boolean checkResourcePermissions(CmsPermissionSet required, boolean neededForFolder) {
  
          if (isMultiOperation()) {
              // for multi resource operation, return always true
              return true;
          } else {
              // check for single resource operation
              return super.checkResourcePermissions(required, neededForFolder);
          }
      }
docs: Checks if the permissions of the current user on the single resource to use in the dialog are sufficient.<p>
  
  For a multi resource operation, this returns always true, checks only for single resource operations.<p>
  
  @see CmsDialog#checkResourcePermissions(CmsPermissionSet, boolean)
  
  @param required the required permissions for the dialog
  @param neededForFolder if true, the permissions are required for the parent folder of the resource (e.g. for editors)
  @return true if the permissions are sufficient, otherwise false