For anyone interested I got this to work. I put a regular box around the subform and used the following code:
Private Sub bxLoadPlanningFocus_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
Dim ctlCurrentControl As Control
Set ctlCurrentControl = Screen.ActiveControl
If ctlCurrentControl = "sfLoadList" Then
sfAvailDrv.SetFocus
Else
sfLoadList.SetFocus
End If
End Sub
Now when I move the mouse over the box frame int sets focus to the subform. This is a contiuous form and to scroll through the record I had to click in the form which had the potential to change data.
anyway, later