The tooltip to display for the item, or %NULL to display no tooltip.
Note that this property has no effect unless the #GtkWidget:has-tooltip property is set to %TRUE on the #GooCanvas containing this item.
The tooltip to display for the item, or %NULL to display no tooltip.
Note that this property has no effect unless the #GtkWidget:has-tooltip property is set to %TRUE on the #GooCanvas containing this item.