1. The "one quiz answer" has been fixed (was fixed quite earlier), but if it pops up again, please tap the ? button at the top of the app, and report a quiz issue there :)
2. Hmm - since the "link another word" is also available in the ... menu (and has become a good, centralized spot for those types of operations), I'll just remove that link (in the screenshot) altogether in the next update.
3. With regards to what I think is the boxes getting sized down a bit too much? I'll need an out-of-quiz, repeatably set of steps (ideally with a video) showing how to recreate it. Sizing issues like that are highly dependent on a number of things on the screen, so I need to see it happen before I'll have a chance of fixing it.
For the missing radicals - what Japanese font do you have renshuu set to?
Thanks. On my end, I tried each of those, but could not replicate the issue. If you could, try selecting just one of them at a time and see if the issue comes back.