Keep list box selection Highligted

[Bob Vance]

When I click on a record in my List box it opens my Horse Info form , but
when i close the form my List box on my main form does not hold my last
selection (Highlighted), where do I start to look to change this?
Private Sub cbActiveHorses_AfterUpdate()

DoCmd.OpenForm "FrmHorseInfo", , , "HorseID =" & Me.cbActiveHorses
If Err.Number = 2501 Then
Err.Clear
Exit Sub
End If

End Sub