When the software finds a file with the extension .HTM(L) it assumes that it is a pre-assembled html file and creates a link to it in the parent document.
While this works as far as it goes it is fraught with difficulties if the HTML file is the least bit complicated as the support files (images etc.) will be treated as available resources and probably end up in the unused document. Also links to other documents and icons will probably fail if they have relative references.
The message is: It you are going to use html documents you have to understand the system thouroughly.
A not-at-all-complicated example is included here and even it doesn't work.
1. Reference in index
If you want the reference in the index (leftFrame) you can add an entry to
the .CH2 configuration file that looks like this:
|right|http://nickerson.icomos.org/steve/|About the Authorit is in the normal format of:
code | frame | data:key | titlebut with "code" blank and the URL in the data field (this is the line in demo.ch2 that creates the index for this demo. Think about what frame you want the reference to use as a document with its own frames can look pretty strange pasted into the frame set here ("parent" is the safest).
2. Reference in document
You can put a reference to an external (or internal) with any of the
link codes {T},{N},{R},{L}.
As you will see from the examples below it is probably a good idea to use the {T} form for anything using frames and for references that might change without your knowledge.