Delete Event not behaving consistently

[RossWindows]

I have this code on a form that is usually displayed through a subform control of another form.

Private Sub Form_Delete(Cancel As Integer)
    If MsgBox("Are you sure you want to delete this note?", vbYesNo, "Confirm Delete") = vbNo Then
        Cancel = True
    End If
End Sub

When the form is being displayed through a subform control:
If a user deletes a record, they are asked to confirm. If the user clicks No, that should be the end of the story, but for some reason, the user is asked a second time.

When the form is being displayed on it's own, the code works correctly and the user is asked only once to confirm the deletion.

Why is this happening?

 

[RossWindows]

I figured out how to fix it, but I still don't understand why it acted like that.

I had to change the form's AllowEdits property to Yes.