Hi Angela,
Yes, CODAP on iPad is finicky. (We’re working on a complete reimplementation of CODAP that will fix this, but its release is still a ways off.) I find that if I touch and hold a bit on the attribute I want to drag, it responds somewhat more reliably. I know this is difficult advice to communicate to a classroom of students, though.
We haven’t seen the issue you mention about the tools sometimes becoming unclickable. Is this something you’re experiencing on iPads or is it something you experience on computers? I’m afraid I only have the usual advice of quitting and restarting the browser (force quitting on an iPad) to give the browser a chance to refresh all its memory resources. If you come across a reproducible case, that would be extremely helpful!
Best,
Bill