Programmatically-created NSWindow slow to resize

Question

If I create an NSWindow by hand:

NSWindow* window = [[NSWindow alloc] initWithContentRect:NSMakeRect(0, 0, 600, 500)
                                               styleMask:NSWindowStyleMaskTitled | NSWindowStyleMaskClosable | NSWindowStyleMaskMiniaturizable | NSWindowStyleMaskResizable
                                                 backing:NSBackingStoreBuffered defer:YES];

…then resizing it is slow and laggy compared to a window from a Storyboard. Why?

Answer 1

Give the window's content view a layer:

window.contentView.wantsLayer = YES;

This is the default for Storyboard windows: