Of widgets and gadgets...
Remember how around WWDC 2004, Tiger had Dashboard "gadgets" instead of "widgets"? And how that was changed for the press releases, but not for the WWDC build of Tiger? Well:
Windows Vista calls its sidebar "widgets", well, "gadgets". - I'm pretty sure Apple has shown Microsoft a bit of Tiger shortly before that WWDC keynote - and then they had to decide which one was going to go with which name. And probably Apple thought they'd rather fight Arlo Rose than Microsoft. ;)