Actualisation des cellules sur une feuille entière...

Private Sub Worksheet_Change(ByVal Target As Range)
  Dim iSect As Range, NoChange As Boolean
  Set iSect = Application.Intersect(Target, Range("A1:Z50"))
  Application.CalculateFull
  If iSect Is Nothing Then GoTo Exit_WorksheetChange
  If InStr(1, Target.Address, ":") > 1 Then GoTo Exit_WorksheetChange
  MetEnCouleurs Target.Row, Target.Column, Target.Value
  Application.CalculateFull
Exit_WorksheetChange:
  Set iSect = Nothing
End Sub

Private Sub Worksheet_Change(ByVal Target As Range)
  Dim [COLOR=blue]Cel As Range[/COLOR], iSect As Range, NoChange As Boolean, [COLOR=blue]Plg As Range
[/COLOR]  ' Définir la plage de mise en forme
  Set Plg = Range("A1:Z50")
  Set iSect = Application.Intersect(Target, Plg)
  Application.CalculateFull
  If iSect Is Nothing Then GoTo Exit_WorksheetChange
  If InStr(1, Target.Address, ":") > 1 Then GoTo Exit_WorksheetChange
  ' Pour chaque cellule de la plage
  [COLOR=blue]For Each Cel In Plg
    MetEnCouleurs Cel.Row, Cel.Column, Cel.Value
  Next Cel[/COLOR]
  Application.CalculateFull
Exit_WorksheetChange:
  Set iSect = Nothing
End Sub