when viewing any subsystem tab of a resource, there is a movable split pane that separates the nav tree from the content area. if you drag this and hit F5, it refreshes back to it's default location. it should remember the relative position the user put it in and move to that position on page refreshes.
rev3044 - make user preferences sticky;
Fixed, rev3078 FF3
This bug was previously known as http://jira.rhq-project.org/browse/RHQ-1563