Replaces the widget packed into the tooltip with custom_widget. custom_widget does not get destroyed when the tooltip goes away. By default a box with a gtk.image.Image and gtk.label.Label is embedded in the tooltip, which can be configured using gtk.tooltip.Tooltip.setMarkup and gtk.tooltip.Tooltip.setIcon.
a gtk.widget.Widget, or null to unset the old custom widget.
Replaces the widget packed into the tooltip with custom_widget. custom_widget does not get destroyed when the tooltip goes away. By default a box with a gtk.image.Image and gtk.label.Label is embedded in the tooltip, which can be configured using gtk.tooltip.Tooltip.setMarkup and gtk.tooltip.Tooltip.setIcon.