Thank you for using Visual Studio and for your commitment to improving it. We are currently evaluating whether we will be able to address this suggestion in a future release. Thanks for capturing the pain points you feel when stepping through multithreaded applications while debugging. We will be providing an update soon.
Additionally, I wanted to clarify that the debugger will only ever complete a step on the thread from which the step was originated. So if you hit a breakpoint, disable it, and then begin stepping you should not stop on a different thread. If you have other breakpoints in your application and another thread hits one, then you will be debugging in the mixed thread state as described in this item.
Program Manager, Visual StudioRobert Schmidt-Cisternas commented
Still broken in VS2017 - the debugger is useless when debugging a single thread out of multiple. I'm using .NET Core and ASP.NET Core.