int Prompt(Callback1<const String&> WhenLink,
           const char *title, const Image& iconbmp, const char *qtf, bool okcancel,
           const char *button1, const char *button2, const char *button3,
		   int cx,
		   Image im1, Image im2, Image im3)
{
........
	int nbtn = !!button1 + !!button2 + !!button3;