don't crash browser/browser tabs when temporarily navigating away from fleet manager page
don't crash browser/browser tabs when temporarily navigating away from fleet manager page

kartben/summit2017,redhat-iot/summit2017,kartben/eclipseiot-testbed-assettracking-cloud,redhat-iot/summit2017,kartben/summit2017,kartben/eclipseiot-testbed-assettracking-cloud,kartben/eclipseiot-testbed-assettracking-cloud,kartben/summit2017,kartben/summit2017,kartben/eclipseiot-testbed-assettracking-cloud,redhat-iot/summit2017,redhat-iot/summit2017