Wi-Fi antenna seems to work when the device is off When I was looking at battery statistics I've found something strange: the bar showing wether a component is running or not indicates that wifi were active when I took off my phone. Is this a bug?
I have a Google Nexus 5 with standard Android 5 on it.

Here the screenshot of statistics :
As Microsoft) used to say:


  That's not a bug, that's a feature.


Check for following: Settings -> Wi-Fi -> Menu -> Advanced:


Scanning always available
Keep Wi-Fi on during sleep