anchor.diff:      (setf (values left-margin right-margin)
             (if (or (typep (slot-value pane 'client) 'menu-bar)
                     (not vertical))
  -              (values *pixie-menubar-item-left-margin* *pixie-menubar-item-right-margin*)
  -              (values *pixie-menu-button-left-margin* *pixie-menu-button-right-margin*)))))
  +              (values *pixie-menubar-item-left-margin*
  +		      *pixie-menubar-item-right-margin*)
  +              (values *pixie-menu-button-left-margin*
  +		      *pixie-menu-button-right-margin*)))))
   
   (defmethod compose-space ((gadget pixie-menu-button-pane) &key width height)
     (declare (ignore width height))
  
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: 
  (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)
    ()
  