Update Event

[YetAnotherActUser]

I would like to raise message after an opporunity changed. The following code works if I make changes to fields and hit save button.

....

 opportunity.Updated += new MutableEntity.UpdatedEventHandler(opportunity_Updated);

....

   void opportunity_Updated()
        {
            MessageBox.Show("test", "test", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }

However, if I make changes to the opportunity Status, sometimes MessageBox popu many times,  sometimes it even stop popup up? Anyone know the exact cause???