fix currentClip == null
fix currentClip == null

openlayers/openlayers,bjornharrtell/ol3,ahocevar/openlayers,ahocevar/openlayers,ahocevar/openlayers,bjornharrtell/ol3,oterral/ol3,oterral/ol3,openlayers/openlayers,stweil/openlayers,openlayers/openlayers,oterral/ol3,stweil/openlayers,bjornharrtell/ol3,stweil/openlayers