Bug or Design?

I have a work for four guitars, one on each of four staves. If I add a hairpin to one part, it also appears in another part:
1.) Select first pitch, then last pitch - it makes no difference if I select the two outer pitches, or if I shift-click to highlight all the pitches; in either case, the pitches on the adjacent staff are not selected/highlighted.
2.) Enter hairpin (with or without mid-point dynamic)
3.) Hairpin(s) appear on two parts

This only happens if the starting dynamic is the same - in this case, both parts are marked piano. Is this intentional? It can certainly save time, but there are many times one part will cresc., while the other(s) remain the same.

I may be missing something (always my default position).

That said, I really like the hairpin-dynamic in the middle-hairpin ability!

Are the identical starting dynamics linked? If so, unlink them before adding the hairpin.
I surmise that when we add a hairpin adjacent to a dynamic, the dynamic and the hairpin are grouped automatically. That’s probably why any other linked dynamics are changed accordingly.

I’m not sure what you mean by “linked.” The first was input, the second alt-clicked; perhaps Dorico interprets that as saying these parts are linked, in some way? How would I unlink them?

Thanks for your response!

When you alt-click on the same vertical line where the original dynamic is copied from (let’s say right underneath on another staff), you copy a dynamic which is automatically linked to the source dynamic marking. Linked dynamics edit together, which is a real time saver 90% of the time, for when you need one staff to be different than the others, right-click that dynamics and choose unlink from the dynamics menu. This will unlink all previously linked dynamics in that column. For removing a single marking and keep the other linked, choose “remove from group”. Grouping is really for the horizontal grouping of dynamics, but can be used in this case to affect a single dynamic in a column

Claude/Florian - thanks to you both. The linking makes sense, now that you explained it. This is where a manual is sorely needed - I have watched the videos, read this board, and so forth. I may have come across this phenomenon in reading, but when I confronted it, I couldn’t recall if I had seen something about this or not. A reference would be really useful. I know it is coming, and the sooner the better!