If Stng_bluestart_checkbox.Checked Then
                  ABlueflap_Bluestart.Visible = True
 -                ABlueflap_Bluestart.BringToFront()
              Else
 -                ABlueflap_Navigateur.BringToFront()
                  ABlueflap_Verrouillage.Visible = False
              End If

C'est exactement pareil que 

 If Stng_bluestart_checkbox.Checked Then
                  ABlueflap_Bluestart.Visible = True
              Else
                  ABlueflap_Verrouillage.Visible = False
              End If
   ABlueflap_Bluestart.BringToFront()