我们在使用NSPopover控件的时候发现弹出的三角区域颜色改不掉
解决方案

    /// popver.contentViewController 这个controller里的viewDidAppear方法中
    NSView *popoverView = [self.view superview];
    [popoverView setWantsLayer:YES];
    [[popoverView layer] setBackgroundColor:WhiteColor.CGColor];
//    白色遮挡箭头颜色
    NSView *tempView = [[NSView alloc] initWithFrame:CGRectMake(popoverView.size.width/2-15, 0, 30, 20)];
    tempView.wantsLayer = YES;
    tempView.layer.backgroundColor = WhiteColor.CGColor;
    [popoverView addSubview:tempView];