Thai typed in a font without Thai glyphs (Source Sans 3, a Latin font)
took the first loaded face that had them, or the first installed file
that did, in path order: on one Windows machine a display face (Kanit)
rather than Leelawadee UI. Characters of Thai, Lao, Khmer and Myanmar
now try fonts made for their script first, installed ones loaded on
demand (Leelawadee UI, Tahoma, Thonburi, Sukhumvit Set, Noto Sans Thai,
the TLWG fonts for Thai), then the fallback as before. Latin beside
them keeps the font chosen.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>