contains_focus
Description:
true if focus is contained in the controllers widget.
See [property@Gtk.EventControllerFocus:is-focus] for whether the focus is in the widget itself or inside a descendent.
When handling focus events, this property is updated before [signal@Gtk.EventControllerFocus:GtkEventControllerFocus:enter] or [
signal@Gtk.EventControllerFocus:GtkEventControllerFocus:leave] are emitted.