Having a Custom "Editor Startup Map" should mark it as "New"

When we open the Default Editor Map (Floor Mesh with SkySphere) and we want to save it, we open up a Save Dialog.

When we have a “Editor Startup Map” set to a different user-made Map, we Save the Editor Startup Map (e.g. when we use File-> Save Current) which overrides it.
I would like to have a Save Dialog here aswell.