Single click reversal
Allow reversal of any selection by clicking again on the selected item. This is not a full turn confirmation or undo but it would solve the accidental click problem. In Connect6, clicking on either of the two new pieces (with the +) should remove them.
There's a possible problem if undo is implemented like this without confirmation -- What happens if:
1. Player A moves
2. Player B moves
3. Player A's screen hasn't updated with Player B's move and clicks on their piece to unconditionally undo their move
Should player B's move be unconditionally deleted?
And as far as UI, wouldn't it be better just to have an "Undo" button which would be common to all games, instead of a different way to undo for each different game?