Luna in cb has 2 minor known problems:
1. roundings : this is due to background color of tab in case image does not load.
2. the width of a hover the selected tab.
Both very minor problems can be corrected in the cb template css file.
Any CSS-aware user around that has time to fix and cross-browser test the fix around ?
Will be happy to integrate a tested fix in next release. just post the fix here and in the CB bug-tracker