When using Hide intensity marking as in the pic below, the vertical spacing of the hairpins changes.
Please excuse me if this is already reported or if I’m doing something wrong here.
I would avoid hiding dynamics in this way: you would be better off simply removing the piano dynamics in this situation.
The problem is that the playback doesn’t work as expected without the detsination dynamic. With no destination the dynamic increases with every phrase.
It seems that it’s the grouping of the Dynamics that is the problem. When only including the harpins in the groups it works fine. So in this case, removing p from the group makes it look great again.
The playback of messa di voce is not yet implemented: only the first half of the swell plays back. This will be improved in a future version.
Ah, that sounds great Daniel! 
And I can’t tell you how much I’m looking forward to that next version! (Even though everything works just fine right now…)