anchor.diff:                         :ink +dark-green+ :line-thickness 5))))))
   
   (define-drawing-test "Ellipse" "Angle transformations" (frame stream)
  -    "Uses internal interfaces. We should see 6 ellipses with limited
  -angle. First four should be filled and should have angle radius drawn. Last two
  -should not be filled (and no angle radius is drawn). Each ellipse is bound by
  -its bounding rectangle and surrounded by four points marking where min-x, max-x,
  -min-y and max-y are (extremum points) are."
  +    "Uses internal interfaces. We should see 6 ellipses with limited angle. First four should be filled and should have angle radius drawn. Last two should not be filled (and no angle radius is drawn). Each ellipse is bound by its bounding rectangle and surrounded by four points marking where min-x, max-x, min-y and max-y are (extremum points) are."
     (declare (ignore frame))
     (let* ((sa (/ pi 2))
            (ea (+ pi (* 3 (/ pi 4))))
  
positive.code: 
  (defun display-backend-output (frame pane &optional benchmark)
    (declare (ignore pane))
    (let ((output (get-frame-pane frame 'backend-output))
          (item (slot-value frame 'current-selection)))
      (let ((description (get-frame-pane frame 'description)))
        (when item
          (unless benchmark
            (window-clear description)
            (with-text-style (description (make-text-style :sans-serif :roman :normal))
              (write-string (drawing-test-description item) description)))
          (labels ((draw ()
                     (with-slots (recording-p) frame
                       (with-output-recording-options (output :record recording-p)
                         (clim:with-drawing-options (output :clipping-region
                                                            (clim:make-rectangle* 0 0 *width* *height*))
                           (clim:draw-rectangle* output 0 0 *width* *height*
                                                 :filled t :ink clim:+grey90+)
                           (funcall (drawing-test-display-function item) frame output))))))
            (if (slot-value frame 'signal-condition-p)
                (draw)
                (handler-case (draw)
                  (simple-error (condition)
                    (clim:with-drawing-options (description :ink +red+)
                      (format description "Backend:~a~%" condition))))))))))
  
  (defun display-render-output (frame pane)
    (declare (ignore pane))
  
negative.code:    (signal-condition-p :initform nil)
     (current-selection :initform nil)
     (application-frame-backend :initform :clx-ttf)
     (frames :initform (make-hash-table)))
    (:panes
     (category-test-pane
      (horizontally (:equalize-height t)
  