Blurry text in a NSTextField

Question

I have a problem with NSFullSizeContentViewWindowMask, the text gets blurry after I added it.

With NSFullSizeContentViewWindowMask: http://cl.ly/image/2t0M1R201d1F

Without http://cl.ly/image/1o0K3d3s3t3j

Code:

self.window.titlebarAppearsTransparent = YES;
self.window.movableByWindowBackground = YES;
self.window.styleMask = self.window.styleMask | NSFullSizeContentViewWindowMask;