Highlight cell upon selection

You could try to work around something like this placed in the sheets code:

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
    If ActiveCell.Interior.ColorIndex = 44 Then
        ActiveCell.Interior.ColorIndex = xlNone
    Else
        ActiveCell.Interior.ColorIndex = 44      '6=yellow  3=red 
    End If
    Cells.Borders.LineStyle = xlLineStyleNone
    ActiveCell.Borders.LineStyle = xlContinuous
End Sub