bug 291033 added the ability to have a "local" profile directory that directory should be salted, like the normal profile dir and, for manually created directories in a path outside of application data, the temp directory should maybe be identical to the profile dir.

*** Bug 296890 has been marked as a duplicate of this bug. ***

FYI, this prevents profile deletion (via Profile Manager) from deleting XUL.mfasl and Cache (assuming the user didn't change their Cache to live inside the salted directory). The reason is that the profile manager assumes that the directory isn't salted because it isn't the only child of its parent: http://bonsai.mozilla.org/cvsblame.cgi?file=mozilla/profile/src/nsProfile.cpp&rev=1.316&mark=1507-1528#1481

AFAIK, this is fixed by using the toolkit code now.