If you have two Frameworks it is possible to share the same users. User details such as the profile, caption, disabled status and password are shared, but separate user authorities for each Framework are stored. Refer also to More details about being signed on as a Different User.
If you want Frameworks to have entirely separate users ensure that the Frameworks have different "User Set" values.
(Go to (Framework) --> (Properties...) -->User Administration Settings tab --> User Set)