This requires you to sniff the browser's history. And most browsers see
this as a security threat so they have blocked that. The followig thread
has some suggestions to get this working:
When you say: This is being used in a CHM that was converted from a Webhelp in RH10, does that mean you are using the feature in RH10 where you are now able to use the CHM as a wrapper in order to present a single .CHM file that presents a skinned WebHelp?
Or are you instead saying that you are now creating CHM output and used to create WebHelp?