How do I tie these notes without destroying the notation in the third bar?
Regardless of my having forced the duration of the relevant notes, the note over the second mezzo-forte dynamic refuses to coexist with a tie on the notes of the first hairpin.
I’ve tried inputting the destroyed note with forced duration on, as opposed to forcing its duration after typing it. No success that way.
(EDIT: I have made available a Dorico file of the afflicted bars.)
I just reproduced your line without a problem.
First step:
Second step: All “bits” of the D receive the “force duration” thing.
Third step: tie every bit, starting from the start (meaning you select the first D and press T twice) :
Thanks for confirming that it should work, @MarcLarcher.
Hopefully, someone can offer a solution that works with more things being equal. To that end, I have isolated my problem in a Dorico file and uploaded it here for anyone who cares to give it a shot.
Well… If I take your file, and proceed like this :
Press U
Then press oo (on 1st and 3rd bits) or o (the second one) to make sure force duration is on, on every bit (three bits) and press T twice when the start of the note is selected, I get
I guess the devil is in the details, and I sense that the solution is about the force duration on every bit right before you tie… oo resets a faulty force duration (but there’s no way of seeing it’s faulty until you start an operation that should work and that fails).
OK so tie the first two notes, then untie them, then reset forced duration on the second note, then tie everything.
Yeah, that does the trick. 
Thanks for the workaround!
