[ Version ( since = "3.10" ) ]
public void set_subtitle (string? subtitle)
Sets the subtitle of the HeaderBar.
The title should give a user an additional detail to help him identify the current view.
Note that GtkHeaderBar by default reserves room for the subtitle, even if none is currently set. If this is not desired, set the has_subtitle property to false.
| this | |
| subtitle |
a subtitle, or null |