The *Tree View* pane on the left-hand side of the browser displays the hierarchical Table of Contents, which can be either **linked-to** or **unlinked-from** the *Current Topic* displayed on the right-hand side. You can toggle between the two modes by pressing the **Link/Unlink Current Topic** icon at the top of the *Tree View* pane.
When the *Tree View* is **linked** to the Current Topic, the *Tree View* will always follow the currently viewed topic, by expanding and highlighting the pertinent section of the hierarchical Table of Contents.
When the *Tree View* is **unlinked** from the Current Topic, the *Tree View* will show only the explicitly selected section of the hierarchical Table of Contents and will **not** follow the topics activated by internal documentation links.