anchor.diff:  
   (defparameter +pixie-selected-tab-bar-view+
     (make-instance 'pixie-tab-bar-view :selected t))
  -
  -
   
   (defclass pixie-tab-layout-pane (clim-tab-layout:tab-layout-pane)
     ()
  
positive.code: (defconstant +pixie-scroll-bar-thumb-height+      34)
  (defconstant +pixie-scroll-bar-thumb-half-width+   8)
  
  (defclass pixie-scroll-bar-pane (pixie-slider-pane) (
     (drag-callback
       :initarg :drag-callback
       :initform nil
       :reader scroll-bar-drag-callback)
     (scroll-to-bottom-callback
       :initarg :scroll-to-bottom-callback
       :initform nil
       :reader scroll-bar-scroll-to-bottom-callback)
     (scroll-to-top-callback
       :initarg :scroll-to-top-callback
       :initform nil
       :reader scroll-bar-scroll-to-top-callback)
     (scroll-down-line-callback
       :initarg :scroll-down-line-callback
       :initform nil
       :reader scroll-bar-scroll-down-line-callback)
     (scroll-up-line-callback
       :initarg :scroll-up-line-callback
       :initform nil
       :reader scroll-bar-scroll-up-line-callback)
     (scroll-down-page-callback
       :initarg :scroll-down-page-callback
       :initform nil
       :reader scroll-bar-scroll-down-page-callback)
     (scroll-up-page-callback
       :initarg :scroll-up-page-callback
       :initform nil
       :reader scroll-bar-scroll-up-page-callback)
     (thumb-size
       :initarg :thumb-size
       :initform 1/4
       :accessor gadget-thumb-size))
    (:default-initargs
       :value 0
       :min-value 0
       :max-value 1
       :orientation :vertical))
  
  (define-pixie-gadget scroll-bar pixie-scroll-bar-pane)
  
  
negative.code: (defclass pixie-menu-button-pane (pixie-gadget menu-button-pane)
    ((left-margin :reader left-margin)
     (right-margin :reader right-margin))                
    (:default-initargs :align-x :left
  		     :align-y :center))
  
  (defparameter *pixie-menu-button-left-margin*  26)
  (defparameter *pixie-menu-button-right-margin* 26)
  