Scenario navigation drop-down
I think it would be nice if there was a drop-down control in the editor that let you jump to a particular scenario. Kind of like the ones that appear for C# .cs files (which navigate by namespace, class and method respectively).
Scenario would be useful. I guess you could have a second drop-down to jump between given/when/then sections too for a specific scenario.
That sounds like cool idea. You mean these ones, right?

I was once thinking about that, but could not find the related infrastructure in the VS extension SDK. (I might be wrong, but as far as I remember at that time it seemed to be a special feature implemented for the internal stuff only. But this was like 4+ years ago...)
If you have time, you can also try to make a bit of research on this. I usually scan through the SDK samples (https://github.com/microsoft/VSSDK-Extensibility-Samples) and/or the documentation (https://docs.microsoft.com/en-us/visualstudio/extensibility/starting-to-develop-visual-studio-extensions?view=vs-2019) we can also ask about this in StackOverflow, the SDK ppl are quite active there. Once we find the infrastructure to be used, the solution should be simple, as we have all the information (scenarios, steps) available for the editor.
No worries. I've actually implemented something similar for an xslt extension I created, so that could be a useful reference.
https://github.com/flcdrg/XsltCop
@flcdrg great. looks good! So it is essentially just a special top margin! Makes sense.