RIPPLE EFFECT when using mouse to click on scroll bar and scroll

Has anyone else had this problem? I have tried 4 new 24" iMac's and ALL FOUR do this! When you click on the scroll bar and scroll down or up, there is a definite "ripple" in the window of what you are looking at. It's as if you put a steel rod under a sheet and pulled it up and down. It only happens when using the mouse to click and scroll. Not with the track ball, not with the arrows, not with the keyboard. I updated Safari, tried using Firefox instead, installed all the OS updates, but it still happens. So far no one in Support has a clue. The display models at the stores didn't do it, but my guess is they are from an older shipment...so maybe this is an anomaly with imac's shipped after April 10.

Try it on your computer and see if it happens. If so, we need to all let Apple know there needs to be a fix. 🙂