To automatically hide the Navigation pane

  1. Open a project (.hhp) file, and then click Add/Modify Window Definitions.

    Adds or edits window definitions and the general appearance of the HTML Help Viewer.
  2. Click the Navigation Pane tab.

  3. In the Window type box, click the window you want, and then select the Automatically show/hide navigation pane check box.

About Customizing the Help Viewer