void ICustomLineNumberMargin.SetOwner(ICustomLineNumberMarginOwner owner) {
			if (owner == null)
				throw new ArgumentNullException(nameof(owner));
			if (this.owner != null)
				throw new InvalidOperationException();
			this.owner = owner;
			if (Visibility == Visibility.Visible)
				owner.OnVisible();
			RefreshMargin();
		}
 void ICustomLineNumberMargin.SetOwner(ICustomLineNumberMarginOwner owner)
 {
     if (owner == null)
     {
         throw new ArgumentNullException(nameof(owner));
     }
     if (this.owner != null)
     {
         throw new InvalidOperationException();
     }
     this.owner = owner;
     if (Visibility == Visibility.Visible)
     {
         owner.OnVisible();
     }
     RefreshMargin();
 }
 protected override void RegisterEventsCore() => owner?.OnVisible();