This could be related to bug 787239

reproduced JON 3.1 ER4.  screenshot attached to document the repro.

Created attachment 586676 [details]
evidence of reproducibility

error in message center ...

Failure in datasource while processing REMOVE request.
Severity :	
Error
	
Time :	
Thursday, May 24, 2012 1:39:50 PM UTC-4
Detail :	

java.lang.ClassCastException:null
--- STACK TRACE FOLLOWS ---
null
   at Unknown.java_lang_ClassCastException_ClassCastException__V(Unknown Source)
   at Unknown.com_google_gwt_lang_Cast_dynamicCast__Ljava_lang_Object_2ILjava_lang_Object_2(Unknown Source)
   at Unknown.org_rhq_enterprise_gui_coregui_client_inventory_common_detail_operation_schedule_AbstractOperationScheduleDataSource_$copyValues__Lorg_rhq_enterprise_gui_coregui_client_inventory_common_detail_operation_schedule_AbstractOperationScheduleDataSource_2Lcom_smartgwt_client_data_Record_2Lorg_rhq_core_domain_operation_bean_OperationSchedule_2(Unknown Source)
   at Unknown.org_rhq_enterprise_gui_coregui_client_inventory_resource_detail_operation_schedule_ResourceOperationScheduleDataSource_executeRemove__Lcom_smartgwt_client_data_Record_2Lcom_smartgwt_client_data_DSRequest_2Lcom_smartgwt_client_data_DSResponse_2V(Unknown Source)
   at Unknown.org_rhq_enterprise_gui_coregui_client_util_RPCDataSource_transformRequest__Lcom_smartgwt_client_data_DSRequest_2Ljava_lang_Object_2(Unknown Source)
   at Unknown.anonymous(Unknown Source)
   at Unknown.com_google_gwt_core_client_impl_Impl_apply__Ljava_lang_Object_2Ljava_lang_Object_2Ljava_lang_Object_2Ljava_lang_Object_2(Unknown Source)
   at Unknown.com_google_gwt_core_client_impl_Impl_entry0__Ljava_lang_Object_2Ljava_lang_Object_2Ljava_lang_Object_2Ljava_lang_Object_2(Unknown Source)
   at Unknown.anonymous(Unknown Source)
   at Unknown.isc_DataSource_getServiceInputs(Unknown Source)
   at Unknown.isc_DataSource_sendDSRequest(Unknown Source)
   at Unknown.isc_DataSource_performDSOperation(Unknown Source)
   at Unknown.isc_Canvas_deleteRecords(Unknown Source)
   at Unknown.isc_Canvas_removeSelectedData(Unknown Source)
   at Unknown.com_smartgwt_client_widgets_grid_ListGrid_$removeSelectedData__Lcom_smartgwt_client_widgets_grid_ListGrid_2Lcom_smartgwt_client_data_DSCallback_2Lcom_smartgwt_client_data_DSRequest_2V(Unknown Source)
   at Unknown.org_rhq_enterprise_gui_coregui_client_components_table_Table_$deleteSelectedRecords__Lorg_rhq_enterprise_gui_coregui_client_components_table_Table_2Lcom_smartgwt_client_data_DSRequest_2V(Unknown Source)
   at Unknown.org_rhq_enterprise_gui_coregui_client_inventory_common_detail_operation_schedule_AbstractOperationScheduleListView$2_executeAction___3Lcom_smartgwt_client_widgets_grid_ListGridRecord_2Ljava_lang_Object_2V(Unknown Source)
   at Unknown.org_rhq_enterprise_gui_coregui_client_components_table_Table$2$1_execute__Ljava_lang_Boolean_2V(Unknown Source)
   at Unknown.anonymous(Unknown Source)
   at Unknown.isc_c_Class_fireCallback(Unknown Source)
   at Unknown.isc_Class_fireCallback(Unknown Source)
   at Unknown.isc_c_Class_fireCallback(Unknown Source)
   at Unknown.isc_c_Timer__fireTimeout(Unknown Source)
   at Unknown.anonymous(Unknown Source)
   at Unknown.anonymous(Unknown Source)

This is UI specific bug.

The backend seems to work correctly and removal of a schedule works through CLI as:

var schedules = OperationManager.findScheduledResourceOperations(<RESOURCE_ID);
var schedule = schedules.get(0); //or just select the one you need
OperationManager.unscheduleResourceOperation(schedule.jobId, <RESOURCE_ID>);

This still requires triage BEFORE anything hits the release branch

master commit 9cb619f40a3cc7609989e9890a1da1f2c8b95273

This was odd. (nod to lkrejci for doing original analysis)
SmartGWT for whatever reason seemed to be getting confused
as to what sort of object that SubjectRecord was. It seems to stem from
setting a ListGrid "object" as an attribute on a ListGridRecord. Perhaps
under the covers it is sometimes a Java object and sometimes a javascript
object. Either way, remove the use of it completely and just use simple
attributes to store the subject name and id.  It adds an attribute but
overall simplfies things (and, as a bonus, works).

Test Notes:
Ensure add and remove are working, as well as the list view "owner" column.

Bulk closing of items that are on_qa and in old RHQ releases, which are out for a long time and where the issue has not been re-opened since.