I’m back on Dorico composing after two years of mixing. So I’ve lost track a bit. I’m trying to create an eighth-note triplet from 2 eighth notes in the space of a quarter note. So I select the first eighth note (or the two eighth notes in a row) and ask for 3:2. Instead of staying in the quarter note space (for 3 eighth notes in a triplet), Dorico spills over into the next bar with links, which I don’t want. What am I missing or forgetting? See gif image.
I hope the eng/fr translation is good.
Just select the chord that has been dragged into the tuplet and alt-right arrow shift it back to where it was.
Okay, I’ll take a look. Many thanks.
p.s. but why is Dorico going there? What’s the logic?
When you create a tuplet, Dorico takes the existing line of notes and drags them into that tuplet. Here you have two quavers followed by a crotchet. Dorico says: I need three quavers to make the tuplet. I’ve already got two, but I need to steal a quaver from the following crotchet… Having stolen that quaver it creates the quaver rest before the next note.
Sounds crazy, but once you get your head around it, it makes perfect sense!
It is this logic that allows you free rein to change note durations (with or without the brilliant Insert mode) in extraordinary ways.
Hi @Mute as a reminder (besides the excellent explication of @Janus), if you want to have immediately what you need for similar cases in the future, you can use the Stop Bar (I hope it is called so…) so Dorico is not allowed to steal the eight note from the next bar 
with shift+alt+I and then create your tuplet (with the shortcut or clicking on the icon).
Thank you all for your help. I’ll take a look at it in the next few days. I don’t doubt that Dorico has the right logic, but you have to know it, and you’re helping me here. I understand better already.
Wow. I never heard of that. Thank you so much!