diff --git a/motif/lisp/internals.lisp b/motif/lisp/internals.lisp
index aa3ddfd922a852da69007262f67c50c7f1aff5f7..73aaf1dedd73399f1464e9c690308c8cac16e678 100644
--- a/motif/lisp/internals.lisp
+++ b/motif/lisp/internals.lisp
@@ -21,7 +21,7 @@
 
 (define-condition toolkit-error (error) ())
 
-(define-condition simple-toolkit-error (toolkit-error simple-condition)
+(define-condition simple-toolkit-error (toolkit-error simple-condition) ()
   (:documentation "An error has occurred in the X Toolkit code.")
   (:report (lambda (condition stream)
 	     (declare (stream stream))