Briggs Softworks

When player is in preflop small blind position, he has the options to check "call xx" (call the rest of the blind) and "Fold on any bet" on the left side.
It's common that players like to just call but would fold if a Bet occurs. Please note that the term call is different from bet.

So it would be reasonable to let players to check both boxes on preflop.

The big blind is the bet you would be folding to so checking the "Fold to any bet" option literally means you will fold your small blind position since it can't be checked. That box is separated from the other "Next Move" boxes because it applies to the remainder of the hand, not just your next turn. What you could ask for is a new "Call x or Fold" option in the Next Move section. But there is a limited amount of space available there so that isn't likely to happen.