After playing a bit, this is definitely not using a consistent set. Additionally, if you shuffle, it doesn't give you the same tiles as you had before, which i

After playing a bit, this is definitely not using a consistent set. Additionally, if you shuffle, it doesn't give you the same tiles as you had before, which is a little disconcerting (and isn't really a shuffle, as it doesn't retain the information about which tiles you had more than one pair of remaining). Lastly, having CTRL-Z work to undo would be helpful.