text box and location of cursor

With regards to a text box in a form, is there a way to
keep text in the same position it was in when the cursor
jumps to another control on a form? For example, I have a
3" long text box, that contains about 20" of text. I am
currently reading a line of text at the 17" mark. I need
to go to another text box on the form, but I want the
text in the current box to stay in the same location -
the line of text at the 17" mark- when I go out of it, so
that I can return quickly to the same position.

Currently, when I click out of the text box, the text
immediately returns to the 'start' position - the first
line of text goes to the top of the text box.