Buttons and layout of the "share" dialog

When the user clicks on the "share" action, a dialog opens and the user can see an input field to add new permission and to choose the rights for that permission. Beneath the input fields, there's a button to "Add permission" (primary small button) that's disabled until the fields have valid inputs. When the user writes the name of a user/group on this field, the button to "add permission" becomes active. When the user clicks on "add permission", this new user/group is added to the list below and the dialog remains open so that the user can continue to add more users/groups. Once the user is done with this task, the user can close the dialog by clicking on the button "Done" (secondary button).