[plt-scheme] Collapse-sexpr

I collapsed an innocent s-expr and look at what Dr Scheme did to it

(define (write-to-users-file s-expr)
            (        with-output-to-file                 u        s   
    e        r        s        -        f        ile
                      (        l        a        m        b        d  
     a         ()
                        (        p        r        e        t        t
       y        -        p        r        i        n        t        
        s        -        e        x        p        r))
                      '        r        e        p        l        a  
     c        e))

I'm using version 300.  I like colapsing the s-exprs because it allows
me to think more abstractly.  Kind of a bummer that this happens. 
Anyone know why or how to prevent it?

-Andrey