I have a MacBook Pro (Retina, 15-inch, Mid 2015, OS X El Capitan, 10.11.5) with Intel Iris Pro 1536 MB connected to an external monitor:
- Resolution: 3440 x 1440 @ 60 Hz
- Pixel Depth: 32-Bit Color (ARGB8888)
- Mirror: Off
- Online: Yes
- Rotation: Supported
- Connection Type: DisplayPort
- Television: Yes
Every time my MacBook wakes up from sleep, all my windows are back to the MacBook screen. I have a similar setup at home (same MacBook but with a Dell 26' monitor) and this does not happen.
Anything I can do about that? If more info is needed, just let me know! Thanks in advance for any help on that!