'Changes the image and label of the widget.
:param newtext: the text that will be used for the label
:param newimage: the stock widget from where extract the image
:param tooltip: the tooltip for the button'

def change_internals(self, newtext, newimage, tooltip=None):

    self.label.set_text(newtext)
    self.image.set_from_stock(newimage, gtk.ICON_SIZE_BUTTON)
    if (tooltip is not None):
        self.set_tooltip_text(tooltip)
