FYI, I was lucky to win some money at the casino on the slots. I received an IRS Form W-2G. They took out FED withholdings. This is how I set it up so my income/tax reports showed correctly.
I created a Personal Income Category titled "Casino Winnings" linked to tax form W-2G Gross Income and a second one for Personal Expense titled "Casino Fed wh" linked to tax form W-2G Fed wh. I could have done a third one for State wh if it had been needed.
Now all my tax reports and Planning Tax Center areas calculate correctly.
Hope this is helpful, Steve