Instead of using stack_length, base the cursor Y position on the
location of the first card in the stack.
To reproduce:
[space] to start game
[down] to move to first maneuvre stack
[space] to select card
[up] move up
[down] move back down to selected card. Cursor is one line too high
[space] deselect card
[space] select card.
The bottom center of the card is drawn with the background color.
