I have extended HttpSessionStore to keep track of the number of active sessions. I increment session counter in method onBind and decrement session counter in method onUnbind. However, method HttpSessionStore.onUnbind is never invoked. onUnbind should be invoked, when session is invalidated. In contrast, method WebApplication.sessionUnbound is correctly invoked, when session is invalidated.
I will try to attach a small project, which demonstrates this bug.