code: public static boolean isScrolledIntoView (Widget target, int minPixels)
      {
          int wtop = Window.getScrollTop(), wheight = Window.getClientHeight();
          int ttop = target.getAbsoluteTop();
          if (ttop > wtop) {
              return (wtop + wheight - ttop > minPixels);
          } else {
              return (ttop + target.getOffsetHeight() - wtop > minPixels);
          }
      }
docs: Returns true if the target widget is vertically scrolled into view.
  
  @param minPixels the minimum number of pixels that must be visible to count as "in view".