[ Version ( since = "3.6" ) ]
public void set_child (Widget? child)
Set a new child for the DockItem.
This child is different from the children using the Container interface. It is a private child reserved for the widget implementation.
If a child is already present, it will be replaced. If widget is null the child will be removed.
| this |
a DockItem |
| child |
a Widget |