From Forum Nokia Wiki

The following change is needed to make this work better in devices with keypad grip and when the keys are locked automatically when the grip is closed.

void CKeyPadLockStatusNotifier::ConstructL()

...
iWindowGroup.EnableGroupListChangeEvents(); -- request to follow new events

void CKeyPadLockStatusNotifier::RunL()

...
case EEventWindowGroupListChanged: -- handle also these events

also the wgId check should be completely removed.