anchor.diff:  ;;;
   ;;;
   ;;;
  -(defclass combo-box (layout widget)
  +(defclass combo-box (%layout widget)
     ((label :initarg :label :initform "")
      (color :initarg :color :initform nil)
      (height :initarg :height :initform 400f0)))
  
positive.code:    (expandable-p :initform t :initarg :expandable :reader expandablep)))
  
  
  (defclass layout (named parent) ())
  
  
  (defmethod compose ((this layout))
    (dochildren (element this)
      (compose element)))
  
  
  (definline make-container-layout ()
    (make-instance 'layout))
  
  
  (defmacro with-style (((&rest path) value) &body body)
  
negative.code: ;;;
  ;;;
  ;;;
  (defclass stacking-layout (expandable panel %layout) ())
  
  
  (defun default-row-height (child-height)
  