Make folder sharing more intuitive

[rsimon]

User feedback:

For me as a new user it was rather un-intuitive how to add collaborators to folders. I had to be careful to click exactly on the user name (not next to it) and then to press Enter to add him/her. I couldn’t understand why it wasn’t working until Anna could show me how to do it properly.

If there is any way to make this a bit more clear to the user I would highly recommend it.