When calling TopicID on HTML5, the navigation div becomes hidden

So I am trying to move towards generating HTML5 output instead of Webhelp Pro, understanding that I will lose the capabilities offered by RoboHelp Server.

However, it is critical for me to have the ability to call topics using a TopicID, because the software calling the help system, which currently calls the html pages directly, will be switching to HelpID calls in the next version (for technical reasons aimed at simplifying everyone's life).

The problem is, these calls are made directly with URLs - meaning, there is almost no possibility that the software code will include the RoboHelp API mentionned in the documentation.

I found a way, through some Googling, to do this. The URL format is: http://yourdomain/path-to-output/index.htm?rhcsh=1&rhnewwnd=0&rhmapno=4321 where 4321 is the TopicID (or MapID, I always get confused between those) that is properly defined and mapped to a topic. However, there's something really strange going on when I use this method to call a page: the navigation (Table of Contents + Glossary + Index) does not appear. More mysteriously, even if I attempt to call a topic normally, the navigation remains hidden. The only way I have to get it back is to close the browser completely and re-open it, then I get my navigation back until I attempt to call the help using an ID again.

The technical detail explaining this (it's NOT a browser bug, it does this in all 3 major browsers, and with 3 different themes) is that the div containing the navigation is set to hidden through a style tag:

<div id="tabbedVPanel" class="wVTabbedPanel" data-showin="NONCSH" style="display: none;">

Understanding that this has to be done through JavaScript somehow, I try to find instances of the ID or the class and wasn't able to locate where the code hides the div, nor did I figure out why it would refuse to show until I reopened my browser. Of course, if I don't use an ID, the style="display:none" code does not appear.

I'm really hoping someone else may  have run into this. I'll continue digging within the code but I have little hope of finding the culprit before going insane.