Copied from our internal investigation: ---------- The problem is in shouldBreakAfter() of Source/WebCore/rendering/break_lines.cpp. static inline bool shouldBreakAfter(UChar ch, UChar nextCh) { switch (ch) { case ideographicComma: case ideographicFullStop: // FIXME: cases for ideographicComma and ideographicFullStop are a workaround for an issue in Unicode 5.0 // which is likely to be resolved in Unicode 5.1 <http://bugs.webkit.org/show_bug.cgi?id=17411>. // We may want to remove or conditionalize this workaround at some point. return true; default: .... shouldBreakAfter() hard coded a line break after ideographicComma and ideographicFullStop regardless any other punctuation right after these 2 characters. ----------------- The above issue is not present any more in ICU 4.0 or later. Chrome uses ICU 4.6. The other major port that uses ICU is Safari. I'm sure Safari Windows uses ICU 4.0 or later. The question boils down to the version of ICU on the earliest version of Mac OS X that Safari has to support. If it's ICU 4.0 or alter, we can just remove two hard-coded cases above (ideographicComma and ideographicFullStop). Otherwise, either we have to detect the ICU version at run-time and do different things or at least we have to fix Chromium and Safari on Windows with #if-def (build-time check). darin or ap, can you tell us the version of ICU on the earliest version of Mac OS X Safari has to support?