Missing feature: the ability, after training a symbol, to click a button whose meaning is "Whoops, I didn't mean to do that". (I gave it some training examples

Missing feature: the ability, after training a symbol, to click a button whose meaning is "Whoops, I didn't mean to do that". (I gave it some training examples for a couple of arrow-type symbols. I forgot to click to switch from one sort of arrow to the other. It now has a left-pointing arrow as a training case for a right-pointing arrow symbol. Or maybe the other way around; I forget which.) Of course that was an utterly boneheaded mistake. But most people -- even among the likely users of this thing -- are boneheaded occasionally. (Looking at the source, it seems that un-training would be quite easy; the app is doing nearest-neighbour classification, and what it stores is just all the examples it's been given.)