docs: function(element) {
          var depth = 3, // limit the search depth
              button;
          do {
              if(OpenLayers.Element.hasClass(element, "olButton")) {
                  // hit!
                  button = element;
                  break;
              }
              element = element.parentNode;
          } while(--depth > 0 && element);
          return button;
      }