[DougWebb]

It's definitely not a common use case, because VS reformats the csproj files whenever it modifies them. Basically, when you make a change within VS that affects the csproj file, the entire file is pulled in through an XML parser into a DOM representation, modified in-memory, then serialized back out to XML. Frankly, I'm surprised comments are retained at all.

[ygra]

XML comments are part of the DOM and are retained, usually. And Visual Studio has become quite good at not clobbering things it does not modify itself. The project files are still normal MSBuild projects, so editing them by hand to add targets of other customisations isn't exactly uncommon.