I missed to thank you for your reply @Bendy, sorry for the delay!
The “top” and "_top" anchors seem to work somehow. A year later i still have not figured out how the above-base vowel marks turn into upstairs tone marks, or second level to first level.
Another thing is that glyphs won’t let me create the ‘calt’ feature for contextual alternates. On click to auto-generate the code the feature disappears.
I created all glyphs for Thai – any accents .small (e.g. maiEk-thai.small) are existing, but not used somehow.
This problem is something most Thai-fonts don’t solve, although some System-fonts seem to manage. I am really stuck here, thanks again for your help.
