I'm not 100% sure, but I think I've read something about this issue in the past few weeks. Can't find it anywhere right now. IIRC, there was a bug (chromium or chrome canary, not sure) that has already been fixed. Maybe Opera is using an older version.
@smnstrk As far as I can judge, the space used in Chrome/Canary is different than the space in Opera beta. The space is slightly shorter but some bookmarks are "out". The good dosage, for me, is Opera stable.