public void onActionDoButtonPush(com.sap.tc.webdynpro.progmodel.api.IWDCustomEvent wdEvent, int Action ) {
  //@@begin onActionDoButtonPush(ServerEvent)
  // If the UI Tree Visitor utility raised any errors, then the error must be cleared before
  // attempting to change the lead selection
  if (!msgMgr.hasExceptions()) {
    IInputDataNode inNode = wdContext.nodeInputData();
    int nodeSize = inNode.size();
    int leadSel  = inNode.getLeadSelection();

    switch (Action) {
      case  0: inNode.setLeadSelection((leadSel-1 < 0)         ? 0       : leadSel-1); break;
      case  1: inNode.setLeadSelection((leadSel+1 >= nodeSize) ? leadSel : leadSel+1); break;
      default: break;
    }
  }
  //@@end
}