Sheet operation Delete Symbol is not deleting

Hello,

I want to delete a symbol by using sheet operations in c#. The operation is executed without an error but the symbol is not deleting

Code:

        public static void DeleteSymbol(ObjectItem oSymbol, Sheet oSheet)

        {

            ExecuteSheetRecordData[] atSheetOperation = new ExecuteSheetRecordData[2];



            Globals.Application.IsVisible = true;

            atSheetOperation[0].Qualifier = (int)ExecuteSheetOperationModes.OpExecSheetDeleteSymbol;

            atSheetOperation[1].Qualifier = (int)ExecuteSheetOperationModes.ArgExecSheetRef2Symbol;

            atSheetOperation[1].Value = oSymbol.Id;



            IList<ExecuteSheetRecordData> list = atSheetOperation;



            Globals.ex_Application.ExtendedUtils.ExecuteSheetOperation(oSheet, ref list);

        }

What did I wrong?

Thanks in advance.

~Philipp~