You may want to change the page zoom level by mouse in small steps.
To increase the zoom level
Press CTRL and roll the mouse wheel forward.
To decrease the zoom level
Press CTRL and roll the mouse wheel backward.
While you are changing the zoom level, if there's something selected on the page, Fred4 will try to keep the selection centred on screen. If nothing is selected, Fred4 will focus on the area close to the mouse pointer.
See also
Change page zoom by keys in small steps