So perhaps it would make sense to think about an alternative for the website version of a topic?
Recently I took a look at the program "ConnectedText" (CT) and I tried out its feature for exporting to HTML / the website version of a topic. It works without frames and I have the impression that it has a better functionality especially when a topic (called "project" in CT) consists of a lot of single documents (called "topics" in CT).
Here a picture of how the index.html of a CT-Project (it is the one that is installed by default) looks like:

---> Instead of a tree with the documents list you have this list on the whole page. And above you have the letters of the alphabet so that you can jump to the document titles beginning with a certain letter.
And when opening a certain document, a page looks like this (in the example it is a small document with the title "Meyer"):

---> Under the title of the document there is a link from which you can return to the Index page (and a second one to the Welcome page).