This was also reported in https://developercommunity.visualstudio.com/t/VS2022-171-Blazor-moving-razor-files-fr/10011429 and https://developercommunity.visualstudio.com/t/Refactoring-namespaces-corrupts-Razor-so/10041958

I can repro this in latest VS

Not sure if this is the same as #6167? Seems like some of the duplicated reports for that issue, are actually this issue.

So we're getting a didChange notification, coming from Roslyn which ultimately comes from Project System which gets its list of changes from Roslyn!

So the next step is to see whether Roslyn is making strange changes (adding whitespace when it should be changing a using statement???) or whether its our source mapping service (which would be called by Roslyn to translate the changes to the .g.cs file to the .razor file) doing something odd.

I suspect nothing else in our system is relying on didChange notifications for .razor files, so we could potentially just (somehow) tell Roslyn not to apply workspace changes to our mapped documents and avoid the issue entirely for now, but obviously fixing things is better, because actually having the using statement change namespace would be magical.

Another report: https://developercommunity.visualstudio.com/t/In-Blazor-app-Razor-file-spaces-insert/1629654

This is because of formatting done by Roslyn. Razor emits code like

// some global usings
namespace MyRazorApp
{

// @using System
using System; // note indentation (or lack thereof)
}

So when the formatting pass happens it indents the using statement

Another report: https://developercommunity.visualstudio.com/t/Renaming-namespace-with-intellisense-sug/1669168