Bruce-
I am not yet using VW2008 (as the interiorCAD2008 plug-in is not quite ready), but have had similar behavior in my current set-up. The palettes re-size or strech-out as in your screenshot, though I would estimate less than 3% of the possible events.
I have lazily attributed the behavior to either rCAD bugginess, an OS problem (Apple Discussions ) which I first thought was a VW problem ( VW Discussion ) , and most adequately, as the ghost in the machine. :crazy:
If the behavior is not tolerable, try upgrading to Leopard, apparently has fixed the OS issue. I'm usually OK to suffer a few anomalies when most things work so well, as we rush headlong into technology only somewhat under control, often patched, pieced, lumped, forgotten, self-generating.....