When I type anything in LibreOffice, it looks like this: https://www.youtube.com/watch?v=zBtF0od8VQg While making this movie, I was typing almost as fast as a regular person speaks. Disabling spellcheck doesn't change anything. The problem seems global. It works like this in all applications, even in the small windows for entering passwords. I think it has something to do with double buffering.
*** This bug has been marked as a duplicate of bug 94035 ***