War — In general — Effects of outbreak of war — Nature of vesting of property in Custodian of enemy property — Person resident in territory of one belligerent as shareholder of company incorporated in territory of other belligerent — Shares vested in Custodian of enemy property of other belligerent — Shares released and dividend paid in lump sum after end of war — Liability of shareholder to tax in country of residence — Whether dividends to be regarded as accruing to shareholder during period of vesting of shares in foreign custodian — The law of Austria.