Let me put it this way:
content
└── windows
└── panels
├── index.md
└── property-panels.md
The the panels folder will produce 1 (one) page (assuming no URL set in front matter and default permalink setup) at http://example.com/windows/panels/index.html.
If you want the property-panels.md to also produce an URL, you have 3 choices:
- Rename index.md => “_index.md”
- Rename “index.md” = “myindex.md” and set “url: /panels” in front matter
- Remove index.md and you would get http://example.com/windows/property-panels/index.html
I wrote the above quickly, but it should be correct. My main point is this: You can disagree about how Hugo works, but it will not change behaviour if you hit it hard with a hammer.