I know this is an old post, but i think i had this issue and all i did was hit the sensor's panel button up there. I think it only works for me on Internet Explorer.
By the way, how are your alerts doing so far? I have 6 sensors and i get weird alerts with each of them.
Sometimes i get the same alert over and over again. For example host X runs ssh (or whatever) on tcp port X.
Also several of my sensors tell me that a specific MAC adress is associated with different IP addresses that has nothing to do with it. And all of that even on the latest version at the moment (6.6) which resolved other issues for me.