4coder is designed to treat the mark as always existing wherever you left it. I believe this is a little different from emacs but emacs is weird and I never really had more than a 10% grasp of it before I switched to 4coder. I don't know what it would mean for the mark to "not exist" in 4coder, you'd have to write a whole new customization layer with a different meaning for the mark.
If the problem you're having is that you accidentally set the mark when you wanted to leave it somewhere else, you may have more luck trying to implement a "mark history" that let's you pop a stack and set the mark to it's previous position. That would also be a pretty big problem, because the setting the mark isn't hookable in any way, so you'd have to track down all the places where you set the mark, and all the places where the default code sets the mark, and modify your mark stack.
If you had that hook, or better yet, the whole mark stack, would that be better for you?
In "notepad" mode you never have a "mark" in the emacs sense, so you can't accidentally set it but you also can't intentionally leave it by a single key press. Instead you have "select a range".