Simon Peyton Jones writes:

Could the table of contents for the GHC user manual have one more level showing? Or just all levels?

Indeed we could show another level. However, I worry that by showing even more headings than we already do we will make things harder to navigate, not easier. Note that Sphinx does offer search functionality (note the search box in the right pane) although I'll admit that it leaves much to be desired. I would really like for this to be improved but in the meantime I wouldn't be opposed to adding another level of hierarchy to the TOC. Cheers, - Ben