Is there a way to auto expand the Topic-Content pane based on content? Instead of having to use the scroll bar inside the pane to navigate the topic content, the pane would extend based on its content. Also, would the same solution work for the TOC? Would like a way to only have one scroll bar for the entire page instead of individual scrolls for each section.
RoboHelp 2017 - Indigo Layout
When this is a requirement, I generally look towards Multiscreen HTML5. That doesn't contain iFrames and is much easier to set up as you describe. (But it has it's own downsides though.)