Widget.grabDefault

Causes widget to become the default widget. widget must be able to be a default widget; typically you would ensure this yourself by calling [gtk.widget.Widget.setCanDefault] with a true value. The default widget is activated when the user presses Enter in a window. Default widgets must be activatable, that is, [gtk.widget.Widget.activate] should affect them. Note that #GtkEntry widgets require the “activates-default” property set to true before they activate the default widget when Enter is pressed and the #GtkEntry is focused.