anchor.diff:  
   (defun display-render-output (frame pane)
     (declare (ignore pane))
  -  (let ((output (get-frame-pane frame 'render-output))
  -        (item (slot-value frame 'current-selection)))
  -    (let ((description (get-frame-pane *application-frame* 'description)))
  -      (when item
  +  (alexandria:when-let ((item (slot-value frame 'current-selection)))
  +    (let ((output (get-frame-pane frame 'render-output)))
  +      (labels ((draw ()
  +                 (with-slots (recording-p) clim:*application-frame*
  +                   (let ((pattern (mcclim-raster-image::with-output-to-image-pattern
  +                                      (stream :width *width*
  +                                              :height *height*
  +                                              :border-width *border-width*
  +                                              :recording-p recording-p)
  +                                    (clim:draw-rectangle* stream 0 0 *width* *height*
  +                                                          :filled t
  +                                                          :ink clim:+grey90+)
  +                                    (funcall (drawing-test-display-function item) frame stream))))
  +                     (draw-pattern* output pattern 0 0)
  +                     (medium-finish-output (sheet-medium output))))))
           (if (slot-value *application-frame* 'signal-condition-p)
  -            (with-slots (recording-p) clim:*application-frame*
  -              (let ((pattern (mcclim-raster-image::with-output-to-image-pattern
  -                                 (stream :width *width*
  -                                         :height *height*
  -                                         :border-width *border-width*
  -                                         :recording-p recording-p)
  -                               (clim:draw-rectangle* stream 0 0 *width* *height*
  -                                                     :filled t
  -                                                     :ink clim:+grey90+)
  -                               (funcall (drawing-test-display-function item) frame stream))))
  -                (draw-pattern* output pattern 0 0)
  -                (medium-finish-output (sheet-medium output))))
  -            (handler-case
  -                (with-slots (recording-p) clim:*application-frame*
  -                  (let ((pattern (mcclim-raster-image::with-output-to-image-pattern
  -                                     (stream :width *width*
  -                                             :height *height*
  -                                             :border-width *border-width*
  -                                             :recording-p recording-p)
  -                                   (clim:draw-rectangle* stream 0 0 *width* *height*
  -                                                         :filled t
  -                                                         :ink clim:+grey90+)
  -                                   (funcall (drawing-test-display-function item) frame stream))))
  -                    (draw-pattern* output pattern 0 0)
  -                    (medium-finish-output (sheet-medium output))))
  +            (draw)
  +            (handler-case (draw)
                 (simple-error (condition)
  -                (clim:with-drawing-options (description :ink +red+)
  -                  (format description "Render:~a~%" condition)))))))))
  +                (let ((description (get-frame-pane *application-frame* 'description)))
  +                  (clim:with-drawing-options (description :ink +red+)
  +                    (format description "Render:~a~%" condition))))))))))
   
   (defun run-drawing-tests ()
     (run-frame-top-level (make-application-frame
  
positive.code:           (drawing-tests-frame (when (eq (type-of frame) 'drawing-app-frame)
                                   (slot-value frame 'drawing-tests-frame))))
        (unless benchmark
          (window-clear description)
          (with-text-style (description (make-text-style :sans-serif :roman :normal))
            (format description "~A~%" (drawing-test-description item))))
        (labels ((draw ()
                   (with-slots (recording-p) (or drawing-tests-frame frame)
                     (with-output-recording-options (output :record recording-p)
  
negative.code: 
  (defmethod handle-event ((pane drawing-app-pane) (event keyboard-event))
    (case (keyboard-event-key-name event)
      ((:|r| :r) (let ((frame (pane-frame pane)))
                   (window-clear (find-pane-named frame 'description))
                   (redisplay-frame-pane (pane-frame pane) pane :force-p t)))
      (:| | (repaint-sheet pane clim:+everywhere+))))
  
  (defun %start-benchmark (this-gadget)
  