Cannot create a project if I haven't got the authorization, but no error is presented

One of our admins came by today and said that he couldn't create a new project after we upgraded JIRA to 6.0, he never had this problem before. I said "phe" and selected projects in the right drop down menu and clicked the "Add Project" button. Nothing happened.
This kind of baffled me so naturally I started up firebug to see what happened and I saw the following error

TypeError: this._enableWebSudo is not a function

It seemed to be an authorization issue but I couldn't figure out why it would happen now after upgrading. I realized, though, that I had never been asked for my admin credentials when going into project so I went in somewhere else in the admin page where authorization was required, filled in my password and after that I could create a project.

So, the problem seems to be that if you go straight to projects and press "Create Project" then nothing happens. There should at least be a message saying "You are not authorized" or something because our admin was really confused.

How to re-create:
Go to projects without having authorized yourself as an admin and press Create Project. Nothing will happen.

Expected result:
If I'm not authorized to create a project either ask me for my password or tell me I shouldn't press the button.

Workaround

This can be worked around with either of the following:

Disable websudo as per our Configuring Secure Administrator Sessions.
Gain websudo access first by accessing a restricted area of JIRA before attempting to create the project (for example access Administration > System).