If I try to use the new "Indigo" layout in RH 2017 with a project that has merged child projects, the TOC works in one direction only.
By this I mean I can use the TOC to navigate to topics in the child projects, but if I move to another page using a browse list, or by searching for another topic and selecting that from the search results, the TOC does not update properly to show the current page selection. If I switch the master project back to the older "Charcoal_Grey" layout, the TOC behaves as it should.
You can re-create this by creating two empty clean projects and linking these to a new master project. The TOC works in both directions on topics inside the project that you're in, but it does not work in the reverse direction for topics in a child project when viewed from the master project. Switching to "Charcoal_Grey" resolves the problem.
Although I can continue to use the "Charcoal_Grey" layout, I do like the new Indigo design and would prefer to adopt it throughout our systems, but without the TOC working in the reverse direction, it's easy to get lost in a large site.
Further to this, I discovered today that the breadcrumb hyperlinks don't appear to work properly in all cases - although this could be a separate problem. I'm testing this further as they sometimes work so I need to identify the circumstances around when they do and don't work.