Sets the focus widget for this.
If focus is not the current focus widget, and is focusable, sets it as the focus widget for the dialog.
If focus is `NULL`, unsets the focus widget for this dialog. To set the focus to a particular widget in the dialog, it is usually more convenient to use [method@Gtk.Widget.grab_focus] instead of this function.
| this |
a dialog |
| focus |
the focus widget |