As I edit any document, and change text, the display goes bonkers. The text inserted is not displayed, or the text deleted is not displayed. What is on the screen is not what is being typed in. Sometimes it eventually corrects by just presume what has been typed will eventually display. Sometimes the screen must be scrolled up/down far enough to get the text off the screen then back on. Sometimes all the text jumps up and down and I must watch for a bit until it settles down.