[plt-scheme] Displaying full error in MzScheme

I am doing some heavy macro programming in MzScheme (via emacs).
Unfortunately, whenever a syntax error occurs, only the first two lines of
the offending expression (which can be long) is printed in the MzScheme
repl, which is making debugging very difficult.  Is there a way to have
MzScheme print the full expression when a syntax error occurs? 

Regards
Andre