Cursor behaviour prevents images from being selected in Firefox and Chromium #708
Description
When using the cursor keys to navigate in Lexxy using Firefox (Linux, Mac) or Chromium (Linux), images are not selected. Furthermore, navigating to the top paragraph doesn't scroll the editor. The cursor moves off screen but the Lexxy editor doesn't scroll as expected.
Reproduced in both Lexxy 0.72-beta and 0.73-beta.
When I use Chrome, Safari or Helium (a Chromium fork) on Mac, it's all fine. Moving the cursor up or down over an image results in the image being correctly selected, and there's no issue with scroll when navigating.
I've verified this issue myself (see video below) and I've had a Linux-using customer report the same problem, as well as reporting an issue where they can't use the arrows to navigate to the bottom of the content because it gets 'stuck'.
Any ideas?