A problem I've had with WordPress a while now is that often when I am writing or editing a long post, either the cursor will suddenly jump up or down; or the cursor might stay in the same place (or thereabouts) but the page scrolls down to the bottom of the WordPress post creation screen (down below revisions to the very bottom).
It's particularly infuriating that it seems to happen especially on longer posts, as you then need to scroll back up and find where you were actually editing! I should also note that I still use the Classic Editor (by virtue of this plugin) and am unsure if this problem exists with those of you who have started to use the new Gutenberg editor.
Anyway, after editing a particularly long post this morning and having to deal with this issue around 20 times (honestly - it was a long post!) I decided to look around for a fix and found that several people had mentioned turning off the distraction-free functionality in the editor... and low and behold it works!
So, what it this setting and where can you find it?
The full-height editor for WordPress looks as you can see above and has been designed to be as "distraction free" as possible. It's meant to allow you to focus on the content you are writing - not a bad thing of course, just not for me.
You can turn off the full-screen/distraction-free editor by scrolling up on your "Add a Post" page and hitting the "Screen Options" slidedown. Then simply untick the option "Enable full-height editor and distraction-free functionality." under "Additional settings". That's it!
Your option change will be saved automatically and you shouldn't have any further cursor or page jumping issues in your WordPress editor screen.