P: CS5 - Unsharp Mask preview - hiccup on Lion 10.7.2

Scenario:
Adobe PhotoShop Version: 12.1 (12.1x20110328 [20110328.r.145 2011/03/28:10:30:00 cutoff; r branch]) x64
Operating System: Mac OS 10.7.2

There seems to be an issue w/ the preview window for sharpening i PS.5.1 on Lion 10.7.2. The issue is not present in Win7 for the same PS version, nor in Mac Snow Leopard, so as far as I can see, it's Lion specific.

Details:
In the sharpening preview window (i.e. Filter | Sharpen | Unsharp Mask, where you alter the radius/amount), you can toggle the sharpening effect back and forth between applied/not applied by click | hold a mouse button inside the preview window. But as you click the mouse, the preview picture is offset in some direction, sort of jumping slightly sideways, making the observation of the effect difficult, as you visually lose track of the sharpening change due to this sudden movement of the preview picture. Here the preview picture should stand perfectly still if clicking|holding a mouse button, as it does in Windows and Snow Leopard. On some rare occasion it may stand still for a click or two, but in 99% it jumps.

Same thing happens either you use a Mac Mighty Mouse or a std. USB mouse, on any mouse-pad or surface, regardless of the mouse config for speed, sensitivity etc.

I do hope this annoying problem can be resolved, as it really hinders a full visual control of finer sharpening routines in PS.