You need to click 'draw' after 3 repetitions to claim the 3-fold draw.
No draws in CHESS?!?

That still isn't chess. After 3 repetitions it's a draw wether the opponents agree with it or not. Obviously someone who is in a winning position won't ever accept a draw.
What is this silly configuration? Are you inventing a new sport? I just played a 15/10 game and we repeated the same moves almost 10 times but the clock wouldn't stop. So I lost the game. I thought you played chess on this site....