Thai works fine with LuaTeX, TeX-fonts and auto-legacy input encoding.
Remove obsolete preamble code,
we now load "fontenc" with Japanese documents by default.
#LyX 2.4 created this file. For more info see https://www.lyx.org/
-\lyxformat 572
+\lyxformat 573
\begin_document
\begin_header
\save_transient_properties true
\maintain_unincluded_children false
\language english
\language_package default
-\inputencoding auto
+\inputencoding auto-legacy
\fontencoding auto
\font_roman "lmodern" "default"
\font_sans "default" "default"
\series bold
after
\series default
-Babel:
+Babel (see preamble):
\end_layout
\begin_layout Quote
# Thai
# babel-thai globally changes catcodes for high-bit chars
# which prevents parsing of utf8 with vanilla inputenc (utf8x works)
-# see also unreliable.wrong_output
-export/export/latex/en-th_utf8_(dvi3|pdf5)_texF
-export/export/latex/en-th_language-default_(dvi|pdf).*
+# see also invertedTests
+export/export/latex/en-th_language-default_(dvi|pdf).?
+export/export/latex/en-th_utf8_(dvi|pdf).*
+# output is correct with 8-bit input encodings and luainputenc (but fails for Scott):
+#export/export/latex/en-th_language_default_(dvi3|pdf5)_texF
+#
# only ASCII characters in DVI (LuaTeX) with non-TeX fonts:
export/export/latex/en-th_utf8_dvi3_systemF
-
# LyX issues
# **********
#LyX 2.4 created this file. For more info see https://www.lyx.org/
-\lyxformat 564
+\lyxformat 573
\begin_document
\begin_header
\save_transient_properties false
\pdfbookmark[1]{\contentsname}{}
\myTOC
\mainmatter }
-
-% Added only for Japanese translation
-% This is needed to use \textquotedbl (this doesn't exist in OT1 encoding)
-\usepackage[T1]{fontenc}
\end_preamble
\options bibliography=totoc,index=totoc,BCOR7.5mm,titlepage,captions=tableheading
\use_default_options false
\output_sync 0
\bibtex_command default
\index_command default
+\float_placement class
+\float_alignment class
\paperfontsize 12
\spacing single
\use_hyperref true
\papercolumns 1
\papersides 2
\paperpagestyle headings
+\tablestyle default
\tracking_changes false
\output_changes false
\html_math_output 0