Even as Finance Minister Pranab Mukherjee has been at pains to reiterate over and over again the economic rationale of his Budget proposal for retrospective amendment of the Income-tax Act relating to overseas merger and acquisition (M&A) deals involving domestic assets, the controversy over the Vodafone tax issue refuses to die down. As could have been expected, the matter cropped up again during the bilateral meeting between the visiting Chancellor of Exchequer George Osborne and Mr. Mukherjee on Monday.