I am not aware of this being specifically mentioned by the tax office but yes it would probably be applicable to taxable income, I am Swiss, if I am living in GB and win the British lottery I would have to pay Swiss tax if I am still tax resident in Switzerland,
So it would depend on your residency not the funds source, even worse if you are an American living in CH and won the Swiss lottery, first they would pay Swiss tax as we tax lottery winnings, then US tax, my GF who is American and Swiss resident pays both Swiss and US taxes