anchor.diff:    (reinitialize-window this))
   
   
  +(define-destructor window (bounds)
  +  (free bounds))
  +
  +
   (defmethod children-of ((this window))
     (with-slots (layout) this
       (children-of layout)))
  
positive.code:     (values width height)))
  
  
  (defmethod compose ((this horizontal-layout))
    (flet ((height-max (value element)
             (multiple-value-bind (el-width el-height) (calc-bounds element)
               (declare (ignore el-width))
               (if value
                   (when el-height
                     (max el-height value))
                   el-height))))
      (let ((height (f (or (reduce #'height-max (children-of this) :initial-value nil)
                           (style :row-height)))))
        (%nk:layout-row-dynamic *handle* height (length (children-of this)))
        (call-next-method))))
  
  
  ;;;
  
negative.code:    (option-mask :initarg :option-mask :initform '())
     (style :initform (make-default-style))
     (layout :initform (make-instance 'vertical-layout))
     (bounds :initform (alloc '(:struct (%nk:rect))))
     (redefined-p :initform nil)))
  
  
  