Help gray wifi icon, turns green only when downloading???

[kittygrade]

I don't understand what's happening with my wifi. It stays gray all the time and turns green only and only when I'm downloading, from the browser or play store. But as soon as I turn off the wifi, it goes back to gray. All google services, internet and sync works. I've tried reboot, clear data and cache, force stop, uninstalling some apps, nothing works.
I use Samsung Galaxy GT-I9300