Create a confluence user with whitespace in their user name, like 'test user'.
Create a home page in their personal space.
From that page like http://confluence.acme.earth/display/~test+user/Home,
click the Tools menu and choose Restrictions.
EXPECTED RESULT: Pages Restrictions popup dialog opens
ACTUAL RESULT: Nothing. Upon further investigation, what is silently happening is a call is being made to getpagepemerssionsaction which is being intercepted by SpaceAwareInterceptor which is returning null in its initial getSpace() call. Thus an HTTP 404 is returned by the AJAX call and thus the user sees nothing.