Maybe this has already been discussed here, but I can’t find it right now. Dorico doesn’t allow a tie and slur on the same note. Normally this doesn’t make sense either, but there are exceptions, such as here:
In this case, the beginning of the slur was placed on the preceding note and then dragged over. Is there a more elegant solution?
Select the first note. Ctrl-click the top notehead. Add the slur S
I’m afraid this is not working here 
Then add slur (S)
I can even select the tied note and the all chord and hit “s” and i get a slur.
Indeed you can!
Either way, I don’t get the slur. If I add the slur first and then tie the note, the slur disappears. (Windows 10, Dorico 5.0.10)
Are slurs-on-ties like buses? You wait for ages, then several come along at once? This question has come up several times in recent days, or am I simply unknowingly stuck awaiting the arrival of an underground rodent?
Slurs can’t start and end on the same note, so when a note is tied into a chord in the same voice, at least part of that phrase is one note “event”. A more reliable method could be to put the upbeat into another voice, force the tie by selecting the start and end notes before tie-ing? If memory serves that should make the slur more reliable.
Sorry, I overlooked this thread. If I change the first note to another voice, it works. Thank you Lillie.
A clarification: Since this seems to have behaved differently for you, Juerg, I am expecting you have set {Engraving Options > Slurs > Tied Notes > starting} to “Start from last note in the chain” by default. That setting does cause this particular slur entry to fail (as one must expect).
You’re right 
. That makes the difference.
I do not understand the musical meaning of a tie and a slur together like this example. Could you please explain? How are you meant to interpret that?
The upbeat note has the upper octave as its target, so it gets a slur, but in turn the note remains, thus has a double function. It is not uncommon in romantic piano music.
I’ve always solved that issue by putting the slur first and the tie after. Doesn’t this work here?
If “Slur starting on tied note” is set to “Start from first note”, as suggested by Mark, it works both ways.
I suppose in terms of meaning the tied note should be a unison in 2 voices, one slurred and the other tied. But this kind of “abbreviation” is found all over piano music.
I still don’t see what the slur acheives sonically.
For computer playback there may be no difference, but in a live player’s emotional response the slur may lead to a smoother transition, say less accent on the second note. I expect such “suggestive” phrasing or slurring marks occur throughout the literature; whether they lead to any specific playing technique from different players is difficult to say.
I think the slur is no different from other slurs. It directs the player’s focus on the target note. Whether the player then emphasises it or not is not essential, but he knows that these two notes are directly related. So it is a mental thing (as with all slurs), which may also have sonical effects. The only difference here to other slurs is that the starting note remains in place, thus generating a second voice, so to speak.
But the slur isn’t on the same note as the tie!