I am still having a problem (running Dorico in English), this is my project:
Monteverdi_Lamento_Chor_1. Teil.dorico.zip (1.46 MB)
I try to add a two staved organ (to paste the Basso Viola da Gambs part into it).
The organ will not show up. Instead the Viola da Gamba changed its name (at some point)…
I can add a three stave organ, but not an organ with two staves.
Could please someone check with the attached file (sorry, it took so long to upload).
If I open any other project, I can add the two stave organ no problem…
As you are using Italian instrument names in the score you will need to download the updated instrument names files and follow the setup steps Daniel has linked to above. After following the steps in that thread I can add a 2 stave organ to your score as expected.
Thanks David,
I followed the steps from this thread:
and got it to work 
