IBM 3270 Manual page 27

Enlarging and Reducing Windows That Do
Not Fill the Screen
If you have changed the size of your windows so
that they do not fill the entire screen, they may
be too small to see very much in them. You can
use them that way. Just move the cursor to the
edge of the active window. When the cursor
reaches the edge, any text that is outside the
border where you can't see it will move so you
can see it. Try it; it really works. You may
decide that you want to make the window larger
so you can see as much as possible and work
more easily.
To enlarge a small window to fill the screen:
1. Use the Jump key to choose the small window
you want to enlarge.
2. Press the Enlarge key once.
The active window will enlarge to fill the
screen completely.
To reduce an enlarged window to its smaller size
again:
1. Press the Enlarge key once.
0 .....
0
The enlarged window shrinks back to its
smaller size. If the window does no't become
small, it is a full-size window. You must
change it size before you can enlarge and
reduce it with the Enlarge key. You can read
about changing the size of your windows in
Chapter 9.
2-8 Book 3- Using the Control Program