[xwiki-users] Page rights management

Hello. I'm having some trouble with the administration of page rights in XWiki 1.7.1. I have a space with certain user rights. Then I assign some rights to a different user in a page in that space, leaving the rest of the boxes blank. As a result, the other users lose their rights in the page. I need to copy the marks from the rights admin to the page rights admin, so that the space users do not lose their rigths in this page. I've read again http://platform.xwiki.org/xwiki/bin/view/Features/RightsManagement and I can't distinguish if this effect is this a bug or a feature. Thank you for your help. JLE