If cash flow is negative after retirement
If your cash flow is less than $0 for years after you retire, the Lifetime Planner sells taxable investments first to cover the shortfall.
If you don't have enough taxable investments, the Lifetime Planner sells tax-deferred investments.
What about taxes?
Whenever the Planner sells investments, it sells enough to cover the cash shortfall and the taxes incurred due to the sale. Note that your portfolios continue to grow due to the rate of return you receive on them, and due to any contributions you may make. The net amount withdrawn is added to your cash flow to bring it to $0.