Hello! Yosemite 10.10.2 My two years old son did something with my laptop. Now I have 5mm shadow line across the screen that is not active. For example: if I drag window to fit all screen - I can't click "close window" button, because it is just under this shadow line. Also my F3 button that shows open grouped applications doesn't work. All other buttons like sound or dashbord work just fine. There is an image. I made red lines to show you where this shadow line is. With that shadow line - Active Corners doesn't work. Any suggestions? Please help, because it is annoying to work like that.