Two quick comments. One, there's been a lot of primitives added since I knew APL some decades ago, some of which would be rather hard to type with a 2741 selectric (equals underbar slash?), and some like jot-dieresis and tilde-dieresis where I think they were just really bored one night and trying to think up the silliest possible overstrikes. Two, how do you get rid of the "pop-up APL keyboard" once you pop it up? Hint: you don't need it, click the Primer tab and you can enter symbols from there.
