anchor.diff:  (defclass enter/exit-arms/disarms-mixin ()
     ()
     (:documentation
  -   "Mixin class for gadgets, which will be armed, when the mouse enters and 
  -    disarmed, when the mouse leaves."))
  +   "Mixin class for gadgets which are armed when the mouse enters and 
  +    disarmed when the mouse leaves."))
   
   (defmethod handle-event :before ((pane enter/exit-arms/disarms-mixin) (event pointer-enter-event))
     (declare (ignorable event))
  
positive.code: 		      :initarg :show-as-default-p
  		      :accessor push-button-show-as-default-p))
    (:default-initargs
     :text-style (make-text-style :sans-serif nil nil)
      :background *3d-normal-color*
      :align-x :center
      :align-y :center
  
negative.code:   (declare (ignorable client))
    (disarm-gadget gadget))
  
  ;;;; ------------------------------------------------------------------------------------------
  ;;;;
  ;;;;  Drawing Utilities for Concrete Gadgets
  ;;;;
  
  ;;; Labels
  
  (defmethod compose-label-space ((gadget labelled-gadget-mixin) &key (wider 0) (higher 0))
    (with-slots (label align-x align-y) gadget
  