slave: StockDecreaseItemSlave
GtkVBox(toplevel):
  GtkTable(table1):
    GtkLabel(label2): 'Description:'
    ProxyLabel(description):
    GtkLabel(label3): 'Cost:'
    ProxySpinButton(cost): '150.00'
    GtkLabel(label5): 'Original cost:'
    ProxyLabel(original_cost): '<span >$100.00</span>'
    GtkLabel(label4): 'Quantity:'
    ProxySpinButton(quantity): '2.00'
