The Chat portlet continues to operate after a user's session expires. Users should not be able to send or receive messages after there session expires.
Note: this bug will also affect any custom portlets that rely on poller. The poller will continue to work after the user's session expires. To fix this issue, the portlet should listen to the Liferay event "sessionExpired", and remove itself from the poller listener queue with Liferay.Poller.removeListener(portletId). For example: