Gtk.RadioButton::group-changed

function callback(radio_button, ):void;

Emitted when the group of radio buttons that a radio button belongs to changes. This is emitted when a radio button switches from being alone to being part of a group of 2 or more buttons, or vice-versa, and when a button is moved from one group of 2 or more buttons to a different one, but not when the composition of the group that a button belongs to changes.

Since 2.4