问题
NSVisualEffectView seems to work just fine in a NSWindow, however it stops working (i.e. does not blur contents behind window) if I set the NSWindow's title bar to be hidden from Interface Builder. I don't see why the two are linked but would like to have a borderless window with the blur working - is this not possible?
来源：https://stackoverflow.com/questions/29596657/nsvisualeffectview-stops-working-of-nswindow-title-bar-is-set-to-hide