Screen density for retina displays

Hi, newcomer here. I used to be an expert programmer, now I do little things for fun. Love Processing so far.
I use a MacBook Pro with 2880X1800 px retina display. Processing doesn’t let me use a window wider than 1440px (1440px fills the screen).
pixelDensity(2); seems to do nothing.
How can I use the full resolution display?