public ColorGradientWidget()
{
this.Build ();
ValueIndex = -1;
eventbox.MotionNotifyEvent += HandleMotionNotifyEvent;
eventbox.LeaveNotifyEvent += HandleLeaveNotifyEvent;
eventbox.ButtonPressEvent += HandleButtonPressEvent;
eventbox.ButtonReleaseEvent += HandleButtonReleaseEvent;
ExposeEvent += HandleExposeEvent;
}