class BlinkingLabel : public Label {
 private:
  Color BackgroundColor[2];
  int currentColor;
 public:
  BlinkingLabel();
  void blink();
  virtual void Paint(Draw& w);
};

BlinkingLabel::BlinkingLabel() {
 currentColor=0;
 //the two Backgrounds between wich is switched
 BackgroundColor[0] = Color(255,0,0) //red
 BackgroundColor[1] = Color(255,255,255) //white
 SetTimeCallback(1000,callback(this,&BlinkingLabel::blink)); //start blinking every second
};

void BlinkingLabel::Paint(Draw& w) {
 Size sz = GetSize();
 if(!IsTransparent())
  w.DrawRect(0,0,sz.cx,sz.cy,BackgroundColor[currentColor]);
  PaintLabel(w,0,0,sz.cx,sz.cy,!IsShowEnabled(),false,false,VisibleAccessKeys()); 
};

void BlinkingLabel::blink() {
 currentColor=1 & ++currentColor; //toggle between 0 and 1
 Refresh();
 SetTimeCallback(1000,callback(this,&BlinkingLabel::blink)); //continue blinking every second
};

...
BlinkingLabel bl;
bl.Transparent(false); //so we arent transparent and our background will be seen
bl.SetText("my background ist switching every second between red and white!");
...