I have for example index.html (file A).
However I duplicate this & work on the fork index2.html (file B) then periodically re-save it as index.html(file A - the main page), this is just so my fork can return to the original when I make errors which is a pretty regular thing.
My idea/suggestion is to have the common save-as in the pages right click menu, so I can save over the main file (or any file/page) quickly.
This may be good in the entire design panel including CSS/JS and even folders.
Cheers
Chris