Created attachment 144100 [details]
Open attachment 143967 [details] from bug 119096 by selecting format 'Text - Choose Encoding', and choose character set 'Chinese simplified (GB18030)'.
=> Some lines are too long, and characters overlap (see screenshot), both with OpenGL enabled and disabled.
Observed using LO 126.96.36.199 & 188.8.131.52 / Windows 7.
Looks fine in 184.108.40.206.
Interestingly in the bibisect repo this was related to a Noto font update in 6.1:
However, in the dialog I didn't change the language, only the character set. Setting the language to Chinese (simplified) as well produces correct-looking document. Should that be needed, though? (I admit not setting both doesn't make a lot of sence)
Your screen clip shows issues both with line formatting--but more so with font fallback--which seems the issue here and makes sense as Liberation Mono has limited coverage of CJK. And, font fallback got major rework 5.2 -> 5.3 with implementation of more DirectWrite use with HarfBuzz.
Believe the "Text" import defaults to using the "Preformatted Text" style form default template and is assigned Liberation Mono.
When I open this, if I choose the GB-18030 encoding and a CJK friendly font other than Liberation Mono--which has limited coverage of the glyphs needed for correct layout--e.g. NSimSun, no issues with fallback or line formatting.
On import believe empty paragraphs/crlf--those with no GB-10830 glyphs--are picked up in the UI local as set. So in an en-US local, I get a mix of Asian - Chinese (simplified) paragraphs and Western - Default English (USA).
IMHO this seems correct, but a CJK user would need to confirm the system local is picked up as the Default for empty paragraphs.
Perhaps retest and adjust the font for the import?
Version: 220.127.116.11.alpha0+ (x64)
Build ID: 0a1a4ffb4f87adff7fbbbc60202b6a0e42fedd0c
CPU threads: 4; OS: Windows 10.0; UI render: default;
TinderBox: Win-x86_64@42, Branch:master, Time: 2018-08-08_23:17:46
Locale: en-US (en_US); Calc: group threaded