No, mostly because everything else looks fine. Calibre 0.5.14 looks fine. It's only Calibre 0.6.x that looks like this.
I did try changing my screen resolution...to be honest, Calibre 0.6.x looks like what happens when I "screen print" something and copy it into Word and shrink it a little. So I thought maybe the Calibre GUI was built at a different screen resolution (or not widescreen, like my laptop). But it made no difference.