Appends a custom item to the list of applications that is shown
in the popup.
The item name must be unique per-widget. Clients can use the
provided name as a detail for the
signalGtk.AppChooserButton::custom-item-activated signal, to add a
callback for the activation of a particular custom item in the list.
Appends a custom item to the list of applications that is shown in the popup.
The item name must be unique per-widget. Clients can use the provided name as a detail for the signalGtk.AppChooserButton::custom-item-activated signal, to add a callback for the activation of a particular custom item in the list.
See also gtk.app_chooser_button.AppChooserButton.appendSeparator.