/// <summary>
 /// Gets or sets whether a given <see cref="PictureBoxStateProperties"/> is set in <see cref="AnimatedProperties"/>.
 /// </summary>
 public bool this[PictureBoxStateProperties property]
 {
     get { return(PictureBoxState.IsPropertySet(this.AnimatedProperties, property)); }
     set
     {
         if (value)
         {
             this.AnimatedProperties = this.AnimatedProperties | property;
         }
         else
         {
             this.AnimatedProperties = this.AnimatedProperties & ~property;
         }
     }
 }