Cannot dispose of custom renderer

Hi,

I wrote a contenview renderer based on the roundedbowview code. It works except when I try to navigate to another page. Then I have the below error:

at Xamarin.Forms.Platform.iOS.ViewRenderer2[BattleQuiz.Controls.RoundedContentView,MonoTouch.UIKit.UIView].Dispose (Boolean disposing) [0x00000] in <filename unknown>:0 \n at MonoTouch.Foundation.NSObject.Dispose () [0x00000] in /Developer/MonoTouch/Source/maccore/src/Foundation/NSObject2.cs:127 \n at Xamarin.Forms.Platform.iOS.Platform.DisposeModelAndChildrenRenderers (Xamarin.Forms.Element view) [0x00000] in <filename unknown>:0 \n at Xamarin.Forms.Platform.iOS.Platform.HandleChildRemoved (System.Object sender, Xamarin.Forms.ElementEventArgs e) [0x00000] in <filename unknown>:0 \n at Xamarin.Forms.Element.OnDescendantRemoved (Xamarin.Forms.Element child) [0x00000] in <filename unknown>:0 \n at Xamarin.Forms.Element.OnChildRemoved (Xamarin.Forms.Element child) [0x00000] in <filename unknown>:0 \n at Xamarin.Forms.Page.OnInternalRemoved (Xamarin.Forms.VisualElement view) [0x00000] in <filename unknown>:0 \n at Xamarin.Forms.Page.InternalChildrenOnCollectionChanged (System.Object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e) [0x00000] in <filename unknown>:0 \n at System.Collections.ObjectModel.ObservableCollection1[Xamarin.Forms.Element].OnCollectionChanged (System.Collections.Specialized.NotifyCollectionChangedEventArgs e) [0x00014] in ///Library/Frameworks/Xamarin.iOS.framework/Versions/8.4.0.15/src/mono/mcs/class/System/System.Collections.ObjectModel/ObservableCollection.cs:161 \n at System.Collections.ObjectModel.ObservableCollection1[Xamarin.Forms.Element].RemoveItem (Int32 index) [0x0001a] in ///Library/Frameworks/Xamarin.iOS.framework/Versions/8.4.0.15/src/mono/mcs/class/System/System.Collections.ObjectModel/ObservableCollection.cs:182 \n at System.Collections.ObjectModel.Collection1[Xamarin.Forms.Element].Remove (Xamarin.Forms.Element item) [0x00011] in /Developer/MonoTouch/Source/mono/mcs/class/corlib/System.Collections.ObjectModel/Collection.cs:134 \n at Xamarin.Forms.MasterDetailPage.set_Detail (Xamarin.Forms.Page value) [0x00000] in :0 \n at ...

Here is the renderer

class RoundedContentViewRenderer : ViewRenderer<RoundedContentView, UIView>
    {

        protected override void OnElementChanged(ElementChangedEventArgs<RoundedContentView> e)
        {
            base.OnElementChanged(e);

            var rcv = e.NewElement;
            if (rcv != null)
            {

                NativeView.Layer.CornerRadius = (float)rcv.CornerRadius;
                NativeView.Layer.BorderColor = rcv.Stroke.ToCGColor();
                NativeView.Layer.BorderWidth = (float)rcv.StrokeThickness;
                NativeView.Layer.MasksToBounds = true;
                NativeView.Layer.BackgroundColor = rcv.BackgroundColor.ToCGColor();
                NativeView.AutoresizingMask = UIViewAutoresizing.FlexibleWidth | UIViewAutoresizing.FlexibleHeight;
            }
        }

        protected override void OnElementPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
        {
            base.OnElementPropertyChanged(sender, e);

            if (e.PropertyName == RoundedContentView.CornerRadiusProperty.PropertyName)
                NativeView.Layer.CornerRadius = (float)this.Element.CornerRadius;
            else if (e.PropertyName == RoundedContentView.StrokeProperty.PropertyName)
                NativeView.Layer.BorderColor = this.Element.Stroke.ToCGColor();
            else if (e.PropertyName == RoundedContentView.StrokeThicknessProperty.PropertyName)
                NativeView.Layer.BorderWidth = (float)this.Element.StrokeThickness;
            else if (e.PropertyName == RoundedContentView.BackgroundColorProperty.PropertyName)
                NativeView.Layer.BackgroundColor = this.Element.BackgroundColor.ToCGColor();
}
}

On a side note I'm surprised that I had to change the layer background based on contentview background. Why wasn't the layer background color already equal to the contentview one?