1. Hmm, is this happening in a particular song? (I'm starting to wonder if the presence of notes in another part, or maybe leading silence is having some impact.) I just tried your procedure in Songs --> Easiest --> "A Tisket, A Tasket" and still had the error count roll back down to zero no matter when I pressed the back button. And I wasn't able to get the error count to increase until after the first song note had been passed.
2. Neat! I like learning those sorts of small details.
3. This is the trouble with not having in-house (or even community) translators. While the translation service we use promises native speakers, they don't have the context of being familiar with the app, so that sort of stuff makes it through sometimes. Sorry! I remember a major problem happened with "Free Play" in about half of the languages. In English, free can mean both "able" (libre) but also "zero cost" (gratis). (The open source community usually distinguishes between the two by saying "free as in freedom" or "free as in beer".) In any event, "Free Play" was translated into the "zero-cost" version of the word in a bunch of languages, which caused lots of confusion.
Regarding the translations you mentioned, which version of language_de.xml are you using? In the latest
language file, "keyLights" is accompanied by the following comment:
language.xml wrote:1: the MIDI channel number that this keyboard uses for light signals, between 1 and 16. The "Ch." is an abbreviation for "Channel", like a television or radio "channel". This is used in a very small location in the application, so it has to be short.
So, I'm guessing the leading "K." in the translation was an abbreviation for channel (or "Kanal"). In English, that line becomes something like "Ch.2 Lights" to mean that Synthesia will use MIDI channel 2 to send out key light messages. Does that clear any of the meaning up?