Private Sub Worksheet_Change(ByVal Target As Range)
Dim r As Range
Set r = Intersect(Target, Range("A2:A" & Rows.Count))
If r Is Nothing Then Exit Sub
Application.EnableEvents = False
If r.Count > 1000 Then
MsgBox "Trop de cellules modifiées !", 48
Application.Undo
Else
For Each r In r
If IsEmpty(r) Then r = [K3].FormulaR1C1
Next
End If
Application.EnableEvents = True
End Sub