Stem direction changes unexpectedly

When I change the note duration from dotted 8th to 16th Dorico changes the stem direction:
2019-04-30 13.24.47.gif
Even trying to force stems down does not have any effect:
2019-04-30 13.25.57.gif
Any ideas what’s happening?

You’re not forcing the stem down in that example - you’re trying to remove a forced stem.

What’s the natural direction of that voice? And where does the green voice originate? On the top stave or the bottom one?

Pianoleo is right, you didn’t click the right option in the second gif. Also, my guess is it’s defaulting to stems up because you have stemlets enabled and the rests are already quite low on the staff so it thinks up is the better way to do it (which, if the other voice wasn’t there, it would be). Try the flip command (f) and see if that solves your problem.

Thanks for your replies.
You’re right of course, the 2nd GIF shows a wrong action, I messed up my GIFs. Sorry!

But also if I select “force stem down” or use “F” to flip - nothing happens.
The green voice originates from a down-stem voice of the top staff.

I attached a project containing just this bar.
Fuga Sept Frank Test 01 - 04_Piano - Fuga IX-XVIII_1.dorico.zip (321 KB)

I can’t tell you why the note won’t click. What I can tell you is that a more sensible option would be to use a downstem voice when you want stems pointing down. Thankfully this is an easy change:

Thanks Leo, super fast and helpful as always!
I can do a kind of workaround that way, but in this piece this would make things quite complicated since starting a new voice is not what is musically happening and I would have to hide rests and / or deal with start and end voice properties each time this occurs. Anyway - I don’t think, what happens here is intended.

The alternative is to select the rest under the start of the beam and turn on its “Rest pos.” property. This turns the implicit rest into an explicit one, and once it’s explicit (real) it can have its stem direction altered.

Okay - that’s interesting. Thanks again Leo for your kind support!

That’s why he’s a “grand senior member” of the forum! Just noticed the title, but it’s most definitely well-deserved.