Three-Time Repetition?

I reached the following position in a game I played recently.

At this point my opponent lost on time. My question is, why did the game not end earlier based on three-fold repetition? It should have been a draw.

Draws by threefold repetition or the 50 move rule must be claimed, they are not automatic.  Next time, press the draw button when the conditions for one of these draws has been met.

Ah, thank you. That clears it up. Now I kind of feel bad for letting the other guy lose on time lol