My Lao font can not typing mkmk in Adobe Illustrator

[Trung_Chau (Trung)]

I’ve been developing a Lao OpenType font with full mark-to-mark (mkmk) positioning to support stacked diacritics, but when I use it in Adobe Illustrator the combining marks fail to stack correctly. Instead of positioning tone marks and vowels on top of one another, Illustrator leaves them in their default positions or drops one of the marks altogether. Because accurate stacking of Lao tonal and vowel marks is critical for correct rendering, I’m looking for guidance on why Illustrator isn’t honoring my mkmk rules and how to fix the issue. Any advice or troubleshooting steps would be greatly appreciated.

[GeorgSeifert]

Did you try in FontGoggles or a browser based font tester?

[Trung_Chau (Trung)]

I tried and it works on FontGoggles and Microsoft Word.

[GeorgSeifert]

Then it is most likely an Illustrator problem. What version do you have?

[Trung_Chau (Trung)]

I’m using Adobe Illustrator version 2025

[GeorgSeifert]

Did you enable Indic support (Preferences > Type > Show Indic options) and use the World Ready composer (paragraph panel > menu in the top right corner > World Ready Composers)?

[Trung_Chau (Trung)]

I enabled Indic support but I can’t see World Ready Composers in paragraph panel

[Trung_Chau (Trung)]

[GeorgSeifert]

It is called “Middle eastern & South Asian Composer” in Illustrator.

[Trung_Chau (Trung)]

I can typing right way now! ຂອບໃຈຫຼາຍໆ