How to reproduce:
Use this txt:

#TITLE:splitting test
#ARTIST:Some Artist
#MP3:song.mp3
#BPM:390
#GAP:0
: 0 6 0 splitme,
E

Open it in the editor and doubleclick anywhere in the note to split it.

Wanted result: splitme + ~,

Actual result: splitme, + ~

I'm aware there's some differences between splitting by keyboard and splitting by the mouse, which I'm actually fine with (I think the keyboard one sometimes places the ~ in a different place?) but I think putting it behind the comma just makes zero sense?

there's probably a bunch of other characters that this also applies to, eg ' (and its variations), " (and its variations), ., :, ; etc. though I'm also fine if we start with just the comma and only add the others as we actually encounter them, so at least implement it in a way that it is easily extensible without having to touch the actual splitting code.

(I know there was at least talk somewhere on eg splitting your into you + ~r, I'm undecided on such ""smart"" splitting. the comma one is different though I think)