code: public void drop() {
  
          // notifying controller, if false is returned, dropping will be canceled
          if (!m_controller.onBeforeDrop(m_draggable, m_currentTarget, this)) {
              cancel();
              return;
          }
          animateDrop(m_draggable, m_currentTarget, m_controller);
      }
docs: Drops the draggable.<p>