Second monitor "black film/opacity"

Hi,

On my second monitor, i have a sort of "black opacity (BO)" :

If i create a second space, on the same monitor, there is no BO on it, but still on the 1st space :

I tried to check the Monitor, spaces, …, in the system pref.

Any ideas ?

Regards,

Teiki.

Mac Pro (mid 201) / MacPro5,1

3,33 GHz 6-Core Intel Xeon

8 Go 1333 MHz DDR3 ECC

ATI Radeon HD 5870 1024 Mo

Mac OS 10.10.3