1. Clicking on any item marker ( • )  will collapse/restore that section of the outline.

2. Shift + clicking an item marker will collapse/restore the first level of that section.

3. Holding down the Control key with either of the above applies the collapse/restore globally from that point.

4. Dragging the pane divider will widen/narrow the outline pane.

5. Clicking on any colored item in the outline will display that item's viewpage. 

Note:

    Javascript must be enabled for advanced outline functions, and special browser options to ignore frame assignments should be turned off.  If a viewpage is a PDF/DjVu/MHT/DOC or similar file type,  your browser must be configured with the appropriate plugin to display that type of file.   More information on this viewer is available here.