docs: public void calcOffset(Container compAnchor, Point offset)
      {
          offset.x = 0;
          offset.y = 0;
          Container parent = this;
          while (parent != null)
          {
              offset.x -= parent.getLocation().x;
              offset.y -= parent.getLocation().y;
              parent = parent.getParent();
              if (parent == compAnchor)
                  return; // Success
          }
          // Failure - comp not found.
          offset.x = 0;
          offset.y = 0;
      }