如何给NSWindow一个特定的背景颜色

import Cocoa

class CustomView: NSView {
    override func draw(_ dirtyRect: NSRect) {
        super.draw(dirtyRect)

        // 设置背景颜色
        NSColor.red.set()
        dirtyRect.fill()
    }
}

class WindowController: NSWindowController {

    override func windowDidLoad() {
        super.windowDidLoad()

        // 创建一个CustomView实例
        let customView = CustomView(frame: NSRect(x: 0, y: 0, width: 500, height: 300))

        // 将CustomView设置为窗口的contentView
        window?.contentView = customView
    }
}