Ability to mark lessons I might want to review later
I find that sometimes I've "mastered" a lesson and still have some doubts about my abilities. I've scraped thru, losing hearts right & left. Some lessons have been much easier for me. I forget which are which, though.
I'd really like the ability to mark the "hard" ones somehow, so I can easily see which I might want to go back to. And it'd also be nice to be able to remove that mark once I feel more confident.
What do you think? Is this something you'd like to be able to do?