I have one new suggestion for file backups dialog. It will be also very helpfull to keep more backup versions from one file.
So my suggestion is to add a new otion like this:

It means that file versions will be named with number behind their name like this:
functions.php.1.bak
functions.php.2.bak
functions.php.3.bak
functions.php.4.bak
functions.php.5.bak
.
.
.
up to maximum number defined in new option...
...including that newly saved ones will be with lesser number. I know it means for program to rename older ones but it is not so complicated. Or it can delete older ones and only create new one with bigger number. But more backups means more comfort while some mistake occures. And back up is used in small number of situations but, when it became it is good to have more files then less.
With regards Tomas