Fixing control-click vs right-click contextual menus in NSView

controlclick.swift

override func mouseDown(theEvent: NSEvent)
{
    /*  Hard-coding this behavior isn't great, and shouldn't be necessary. (It should
        be up to OS X to define what a contextual-menu click is/isn't, and we should
        only care about vending our NSMenu via `menuForEvent:`). */
        
    let modifierFlags = theEvent.modifierFlags;
    
    if (modifierFlags.contains(.ControlKeyMask))
    {
        if let menu = self.menuForEvent(theEvent)
        {
            NSMenu.popUpContextMenu(menu, withEvent:theEvent, forView:self);
        }
    }
}