Refund and Capital Gains

Hello my wife and I have about 90K in W2 income. She acquired stocks from her grandmother which my wife sold and had around 8500 in capital gains. When the investment advisor talked to her in April the Investment Advisor said she would be paying around 1000 in Federal Taxes. As I was doing the turbotax forms and inputting all the information in I see that "Tax on this income is included in your total tax due of 0? This amount may change as you work on your return". So why are we not taxed on this capital gain then?