Sp2: certain fields (page field, big text field;...) are not locked in read-only mode when a user (or the workflow) put a lock on the container

With IE, I open my workflow from the home page with root (so everything should be locked).

With FF and another user (steven), I try to edit one of my topmenu container. The action menu correctly displayed the menu in greyed mode. However if I click on the update action, I can still edit the page field or the Description big text metadata... nothing is saved at the end... but users should not have the right to modify something which will not be saved at the end. This is confusing from an end-user point of view.