What do my facebook messenger notifications mean?

[sidbstard]

In my android notification bar I get my usual messenger icon which has the white circle and black lightning. But next to it I have one with black circle and white lightning. Is this a secret conversation or something?

 

[SpookDroid]

Nope, it's a running indicator (I think it usually shows up when you're using Chat Heads). If you check your unread messages, the white icon clears but the black one remains if the chat head is kept 'open' or floating. If you close the chat head, the running indicator goes away. It's now a security feature to let you know which apps are running/displaying over other apps since this method could (very unlikely...but could) be used to 'mask' your apps for your password inputs,for instance.