Path: Step-by-Step view, Investment Income, Stocks, Sales entry
The screen for proceeds and cost basis requests a Sale Category with pull-down menu. The pull-down menu does not include "Box X". The software then shows this as a error if a selection is not made and arbitrarily assigns the Sale Category as Box C (on the summary screen) if no selection is made.
The Form view, however, handles this correctly, and offers "Box X" in the pull-down menu. However, Turbotax does not display this correctly if one then goes back to the Step-by-step view and edits the entry.