A Unity ID allows you to buy and/or subscribe to Unity products and services, shop in the Asset Store and participate in the Unity community.
Separate names with a comma.
Same issue here as well. The strange part is that the command line that Unity specifies it executed doesn't include that "unknown option".
As far as I can tell it works great! A huge improvement to the previous basic UI system. Even for a very simple use case the old UI was pretty...