visible_child
Description:
The widget currently visible when the leaflet is folded.
Note:
See [the migration guide](migrating-to-breakpoints.html#replace-adwleaflet)
The transition is determined by [property@Leaflet:transition-type] and [property@Leaflet:child-transition-params]. The transition can be cancelled by the user, in which case visible child will change back to the previously visible child.