Scroll Text position RESET?

I know this is a dumb question, but it would’ve taken me forever to search through all the rest of the posts regarding Scrolling Text boxes.

So I have text scrolling in a dynamic text box. Buttons control it’s movement, up and down with (scroll --) and (scroll ++).

Let’s say I read to the bottom of this text, and then load a new file into this same box. When I do this, the new text is scrolled to the bottom.

My Question:
How do I reset the scrolled position back to the top** for each new file that I load??**