Is there anywhere I can view a list of the context points that have been captured/converted from my .h file? I've tried a couple of locations in the output, and seen either a couple of random ones from my file, or one that does not exist in my original files at all.
Not entirely sure what you're looking to see. The .h file is just your MapIDs built from the CSH markers in your FM content.
I'm hoping to see a list of the CSH markers that actually made it to the output files, as none of them are there now, and before the upgrade to FM16/2020, there was no issue. I can test our software with old versions of the help, and new versions. The earlier versions have context sensitive working, the new ones do not. Nothing was changed other than the "this was created in a previous version, do you want to update?" acceptance.
The .h file in this case is manually maintained.
If the resulting help output doesn't have your CSH marker indicators in the HTML, then something's gone sideways in the Publish process, I suspect. Have a look at your settings and reselect the setting for CSH markers. I'm not sure how (or why) you'd have to manually maintain the .h file.
That's the problem. The markers are there, but something in the java 'magic' is not translating them correctly. If I replace the files with a group made from FM2019, they work fine. The .h file was inhereted, so I've just maintained it (mostly incase it got renumbered if I added new ones) and it had never been a problem.
Where in the settings is anything for CSH markers? I've been looking, and can't see anything other than where to add a new (unstructured) CSH marker.
Hmm, just had a look in FM2020 - I was expecting to see the same control that's exposed in RH Classic versions - it was labelled "Context-Sensitive Help Marker" in RH's FM Conversion Settings > Other Settings sub-section - in the Style mapping tab (General Settings sub-section), but it's not there.
I'd give the FM folks a buzz - see https://helpx.adobe.com/contact/enterprise-support.other.html#framemaker for your support contact options.
Hmm, looked some more - looks like you have to use the Insert > Publish Markers > Apply CSH Marker to your FM content to get them in; doesn't seem to support your own custom CSH markers like in the FM to RH route. Time for a Tracker (https://tracker.adobe.com/) item I think.
I'm not sure the tracker item correctly identifies the problem. I think the functionality may have been broken in FM 2020. It works fine in FM 2019 to generate a help file with CSH with custom-defined CSH markers. It's just that when you use FM 2020 to generate HTML help with CSH with the exact same source and custom .h file, it no longer works. Maybe there are some extra steps that need to be take in FM 2020, but using the exact same process as FM 2019, and following the documented way to generate HTML help with CSH (as linked to above) doesn't create help with functional CSH.