How to set Blazor Web App UI to use static port?

In .Net 9, If you create a Blazor Web App, in development, the user interface always start on a dynamic port.

I'd like to always start on a statically defined port.I've updated launchSettings.json to do that for for https, I think...

{"$schema": "https://json.schemastore.org/launchsettings.json","profiles": {"http": {"commandName": "Project","dotnetRunMessages": true,"launchBrowser": true,"inspectUri": "{wsProtocol}://{url.hostname}:{url.port}/_framework/debug/ws-proxy?browser={browserInspectUri}","applicationUrl": "http://localhost:59301","environmentVariables": {"ASPNETCORE_ENVIRONMENT": "Development"        }      },"https": {"commandName": "Project","dotnetRunMessages": true,"launchBrowser": true,"inspectUri": "{wsProtocol}://{url.hostname}:{url.port}/_framework/debug/ws-proxy?browser={browserInspectUri}","applicationUrl": "https://localhost:59300","environmentVariables": {"ASPNETCORE_ENVIRONMENT": "Development"        }      }    }  }

But it always chooses some random port every time it loads in development.

Is this a Kestrel issue? The AppHost sites always come up on the launchSettings URL & port set in that project.

I've verified that the 59300 port is not in use with netstat

netstat -ano | find "59300"

How can I force the user interface development site to always come up on a port like 59300 for https?