CMs cockpit "quick edit" issue

In CMS cockpit ,when I click ,"Quick edit" button in Live edit then ,it is throwing exception as Failed to stop server-push, org.zkoss.zkmax.ui.comet.CometServerPush@79cde6b3 java.lang.NullPointerException at org.zkoss.zk.ui.impl.HybrisUiEngineImpl.addResponse(HybrisUiEngineImpl.java. please tell me the reason. Thanks, Chandan