cocoa - How to implement a window just like the quicktime player open file dialog in osx 10.10 -

quicktime player open file dialog has no close/min/max button in toolbar , @ same time, dialog has capacity resize, go through cocoa interface build , try set 1 window "style" it, haven't found one, can set window mask using nsresizablewindowmask, show close/min/max button, can hide these buttons still occupy space in toolbar though hidden, know how achieve quick time player open file dialog's design?