void CheckFontChange(object sender, PropertyEventArgs e)
		{
			if (e.Key == "DefaultFont") 
			{
				FontContainer.DefaultFont = FontContainer.ParseFont(e.NewValue.ToString());
			}
		}
		protected virtual void OnPropertyChanged(PropertyEventArgs e)
		{
			if (PropertyChanged != null) 
			{
				PropertyChanged(this, e);
			}
		}