Thanks, guys! We are fixing the issue with take-backs!
Thanks.
There is something else that has changed which I think needs fixing as well.
It used to be that the user could control which colour they would play by clicking on the 'Finish v Computer' button from a position where the colour they wanted to play was the colour whose turn to move it was. e.g. If you want to play as black you click on 'Finish vs Computer' when it's black's turn to move.
This no longer works. Now it does not seem possible to control which colour you will be from the position when you click on 'Practice vs Computer'. You can 'Switch Sides' afterwards but I think the old way of controlling your starting position and colour should be restored as well.
Thanks!