     }
     override public func mouseExited(theEvent: NSEvent)         { if mouseOver.value { mouseOver.value = false; } }
     
-    private var _trackingObserverLifetime: Lifetime?;
-    
     ///
     /// Sets up the observers for this view
     ///

    /// Lifetime of the drawReactive() call
    private var _drawLifetime: Lifetime? = nil;
    
    public override init(frame frameRect: NSRect) {
        super.init(frame: frameRect);
        

            case NoTracking
        }
        
        let needsTracking = Binding.computed({ [unowned self] () -> NeedsTracking in
            // If something is observing the mouse position...
            if self.mousePosition.isBound.value {
                if !self.anyMouseDown.value {
