Could there be another little bug in LuaLatex font handling?
Take the following example:
\documentclass{article}
\usepackage{fontspec}
\setmainfont{Gentium Basic}
\begin{document}
xa?x
\end{document}
When compiling with LuaLatex, the dots end up on top of the x, not on
top of the a. The output is correct in XeLatex.
Note that the รค is produced (in the source code) from a + combining
diaeresis. (In this particular case, I could of course just use the
normal Umlaut character, but I have more complex cases where I need
combining diacritics.)
Thanks,
Yves