Problem

In Confluence 5.4.x, if you hide one of the links in the application navigator (Confluence Admin > Application Navigator), it is not possible to unhide it as the part of the row where the Update button should be is blank.

Cause

This is caused by an undocumented bug.

Resolution

This problem is resolved in Confluence 5.5. Upgrade to that version or later to be able to unhide links in the application navigator.