Puggo - Jar Jar's Yoda said:

In a way -- a prominent longtime poster uses that exact avatar.

Thanks... that's actually even worse. Fixed that. :)

CatBus said:

Actually the muxer (tsmuxer or mkvmerge) just converts the SRT files into a BD-SUP file on-the-fly and you never see it, so the muxer is the software creating a bad BD-SUP file. No problem though--you can just demux the results to get the actual BD-SUP file it created. Then import/export the file in BDSupEdit, and then remux the whole thing again, only this time mux your fixed BD-SUP file instead of the SRT file.

Er, I think... ;)

Tried that, to no avail. But I found the culprit: It's VLC! Tried to play the muxed file with Media Player Classic. It shows the subtitles just fine. No need to edit them with BDSupEdit. The problem with the lines, that wouldn't fit on the screen, is solved too. The default font size in tsmuxer is too big. Changed it to a smaller one before muxing and it's fine (duh me!).