Depending on the font, Thai vowel marks appear before the character they should be combined with. Steps: 1. Install latest Leopard dev release build (9A499) 2. Open URL 3. Click on the "Display" button Result: a table appears listing Devanagari, Arabic and Thai with different fonts set. Scroll down to the Thai font "Ayuthaya". The first glyph in the string of Thai characters is a vowel mark, it should be rendered above the next character. Same for some font substitution cases, Andale Mono, Courier, Monaco. For more background: https://bugzilla.mozilla.org/show_bug.cgi?id=392209 Seems like the way ATSUI does font substitution has changed in 10.5. Confirmed with Webkit nightly r25168.
Created attachment 16105 [details] testcase screenshot
<rdar://problem/5435331>
Thanks for the bug report, John! However, this bug should have been filed in Radar at <http://bugreport.apple.com/> at not in WebKit Bugzilla for two reasons: 1. It is not a bug in WebKit. 2. The bug is in a developer release of software covered by an NDA. I have created a Radar for this, and will now close this bug as RESOLVED/INVALID for the above reasons. Note that you may use <http://connect.apple.com/> to create a free "online" account for use with bugreport.apple.com.