Logout - member of group everybody must click twice

I need to click twice on logout in order to effectively log out, if I am logged in as a user belonging to everybody.

STEPS:
------

• log in as user 'admin', password 'admin'
• add a user everybody/everybody
• make everyody a member of the group everybody
• log out
• log in as user 'everybody', password 'everybody'
• once you are in, click on Logout [x] in the upper right corner, and notice an animation on the Hippo in the upper left corner.
• from here, two options:
• - click on Logout [x] once more and you are taken back to the login page
• - wait a little while, and you are taken to the login page

In both options, you will be granted by a message saying "Session expired, please login again."

See also: http://issues.onehippo.com/browse/CMS7-4020