EditOperation.ShowProgressor property doesn't work. I set it to false but progress dialog is shown anyway. I saw your code with dotPeek and came to this awful workaround:
var editOperationType = typeof(EditOperation);
var progressorProperty = editOperationType.GetProperty("CancelableProgressor", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic);
if (progressorProperty != null)
Can you fix EditOperation.ShowProgressor property logic?