code: public ElementUI getNextSibling(boolean visibleOnly) {
          ElementUI parent = getParent();
          
          if (parent != null) {
              int count = parent.getChildCount();
              
              for (int i = getIndex() + 1; i < count; i++) {
                  ElementUI child = (ElementUI) parent.getChild(i);
                  
                  if (!visibleOnly || child.isVisible()) {
                      return child;
                  }
              }
          }
          
          return null;
      }
docs: Returns this element's next sibling.
  
  @param visibleOnly If true, skip any non-visible siblings.
  @return The next sibling, or null if none.