In the editor if you set the “Attacks Enabled” field to “Attack 2 Only” for a nomal unit, when selecting the unit Attack 2 will be placed on the lefthand side where attacks normally are placed, but this is not the case if you do the same for a Hero. This is particularly problematic since it means the attack isn’t visible at all on the Hero because the Heroes stats on the right side cover up where Attack 2 would theoretically be if both attacks where enabled.
I’m aware that Attack 2 is used for Orb attacks vs air for melee heroes, but there’s no reason why the attack should be hidden if you make a custom hero where it’s the only one enabled.