Private Sub Worksheet_BeforeDoubleClick(ByVal Target As Range, Cancel As Boolean)
If Not Intersect(Target, Range("A1:A1000")) Is Nothing Then
If IsEmpty(Target) Then
Target = "P"
Cells(Target.Row, "B") = Date
Else
Target = ""
Cells(Target.Row, "B") = ""
End If
End If
End Sub