To enable Natural Search for HMTL Help 1.x (.chm), NetHelp (.htm) and WinHelp 4.0 (.hlp) targets:
1. Select the desired Help target from the Project Editor.
2. In the property pane, set the SearchEnabled property to True.
Note: Make sure the GenerateProjectFile property is also set to True (HTML Help and WinHelp only). If you have the GenerateProjectFile property set to False, you will need to manually edit the .hhp or .hlp file to enable Natural Search. For more information, see Manually Adding Natural Search Support.