Hi, Marijn,
We recently noticed a Chrome issue where cursor jumps to the beginning/end of a document if arrow up/down is blocked by large contenteditable=false block,
I created a small example to demonstrate this issue: https://glitch.com/edit/#!/electric-band-honeycrisp?path=index.html%3A22%3A0
Do you have any suggestions on what is the best way to workaround this issue?