I'm usually using HGP行書体 size 24.
In this example however it was HGP明朝B, happened to both.
Due to your hint I just did following experiments:
MS ゴシック* 24 still happens
MS ゴシック 12 still happens...actually does the text size even matter? It resizes the text on its own in test/learning mode.
MS 明朝* 12 still happens.
(those are gothic and minchou in japanese)
Of course I changed the font and then closed and reloaded the file in order to make the changes apply.
(on a sidenote: how about a little popup that tells you something like 'You have to reopen all active files which use that language for the changes to apply' (best would be with a checkbox, 'do not display this dialog again') this could help users. Perfectly unimportant, just saying there is room for improvements)
Back to the main topic...a file that shows this behavior? No problem. This I don't really know your E-Mail address I took the liberty of uploading it at rapidshare. I'm terribly sorry to cause an inconvenience, but it should not too bad since files of that size do not have a wait time (I think).
http://rapidshare.de/files/21005040/evillinebreak.szm.html(Note the defitions are, if not marked otherwise, taken from koujien fifth version and are therefore...property of the author? Anyways just wanting to point out for legal reasons that there are small parts of this product contained)
To reproduce just go into testing/learning mode, wait till you find an entry with multiple subpoint (which are...most of them?) and resize a bit...you will encounter disappearing lines. That is at least how it's here.
Thank you for your effords...and good luck with this one. If you cannot reproduce or fix it...then never mind.