See also VS 2010 Help Debugging
HTML Help Workshop had a command "HTML Help Messages" that enabled you to view low-level messages logged by the HTML help engine.
You can do the same in MS Help Viewer 1.0 and view useful stuff like URL commands being processed.
and set DebugMode=true.
Restart the Agent tray application and the Windows Event Log now shows Agent debug.
This gives a lot of noise like memory lock and unlock messages.
To enable verbose logging ()
and set LogLevelVerbose=true