Welcome to our community, Donna
Hoping you are using RoboHelp HTML here.
Edit the properties of your Microsoft HTML Help layout. Click
the Edit... button to the right of the "Advanced Settings". Click
the TOC Styles tab and make the following changes:
* Enable the Always Show Selection
Dismiss the dialog and open the Project Setup pod. Edit the
Window properties for the .CHM. Note that you may actually need to
define a window. If you see a window icon with a globe in it,
that's a WebHelp window definition.
So you edit the Window properties and ensure the
"Auto-synchronize TOC" option is configured.
After that, simply compile the .CHM and ensure the window is
defined as the default!
Cheers... Rick