Dear Kovid,
thank you for your wonderful work.
I come here from bug report #1843558 which I filled today to give you feedback on the Japanese Language support.
I confirm now vertical-text works correctly, but there are a few bugs that appear only for Japanese ebooks.
I attach some screenshots.
1) The first error (error 1 in the screenshots) appears on some Japanese ebooks when opening the file. I attached an ebook for which the error appears so that you can test it yourself.
2) The second error is viewed when using the arrow keys to change page. Basically now I can only "jump sections", but I cannot manage to turn page normally.
Thank you again for your support!
Warmest Regards,
Jacopo
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