No specific UI feedback on "Display name" missing while creating a new user, except for save button being disabled

[rowasc]

Expected behaviour

• I see an error/warning letting me know that I have to fill in the display name.
• Error text: "Display name is required" (ie: like all other required fields)

It should look like this:

Actual behaviour

I don't see an error or warning unless I edit the display name field and delete the content.

Steps to reproduce the behaviour/error

• Login as an admin
• Go to settings/users
• Click on + to add a user.
• Fill in email and password.
• • The save button is disabled, but I don't know why.

Aha! Link: https://ushahiditeam.aha.io/features/PROD-515

[rowasc]

Not a blocker, but it's really confusing if you don't realize the display name is there and required.

[rowasc]

cc @jshorland probably low priority considering all things, but still a weird behavior, I think