I've been seeing many complaints about having a "black tabs background" or "black title bar". I myself have this too.
When Chrome is maximized, you'll see the bar behind the tabs, the new tab button and the maximize, minimize and close button all to be black.
This also apparently seems to be happening only for XP users and not Vista.

I'm thinking Google's trying to play around with Vista's window transparency capabilities. It seems they forgot XP doesn't have this feature.

Well, I guess you can't expect everything to be perfect. Its the dev version afterall...

Wow, you're right, it only happens in maximized mode.

You can tell it isn't on purpose, it has to be a mistake and I guess it will be fixed in another release, so I'm not worried.

To fix it now, use my theme :
[Release] Original Theme for 2.0.180.0