Private Sub Worksheet_BeforeDoubleClick(ByVal Target As Range, Cancel As Boolean)
Application.ScreenUpdating = False
lastrow = Cells(Rows.Count, 1).End(xlUp).Row
Set Target = Range("B1:B" & lastrow)
'The following for loop updates formulas in column A to absolute references. _
Delete if not necessary.
For Each c In Range("A1:A" & lastrow)
c.Value = Application.ConvertFormula(c.Formula, _
xlA1, , xlAbsolute)
Next c
Range("A1:A" & lastrow).Copy
Range("B1:B" & lastrow).PasteSpecial Paste:=xlPasteFormats
Range("B1:B" & lastrow).PasteSpecial Paste:=xlPasteFormulas
Application.CutCopyMode = False
Application.ScreenUpdating = True
End Sub