The ::device-changed signal is emitted whenever a device has changed in the hierarchy, either slave devices being disconnected from their master device or connected to another one, or master devices being added or removed a slave device.
If a slave device is detached from all master devices
GdkDeviceType will change to
if it’s attached, it will change to
The default handler is called after the handlers added via
The data is owned by the caller of the function.