Macro VBA for Automatic Row Coloring

To answer your second question first - you cannot undo a marco

Try this version:

Sub auto_open()
DerCell = Selection.Range("A2").End(xlDown).Address
Set MyPlage = Selection.Range("A2:" & DerCell)
Dim MyDate As Date
    MyDate = Now + 7
    
    For Each Cell In MyPlage
Set colRange = Range(Cells(Cell.Row, 1), Cells(Cell.Row, 3))

        If Cell.Value = [D10] Then
            colRange.Font.ColorIndex = [D10].Font.ColorIndex
            colRange.Interior.ColorIndex = [D10].Interior.ColorIndex
        End If
        If Cell.Value = [D11] Then
            colRange.Font.ColorIndex = [D11].Font.ColorIndex
            colRange.Interior.ColorIndex = [D11].Interior.ColorIndex
        End If
        If Cell.Value = [D12] Then
            colRange.Font.ColorIndex = [D12].Font.ColorIndex
            colRange.Interior.ColorIndex = [D12].Interior.ColorIndex
        End If
 Set colRange = Nothing       
    Next
End Sub