Description

Given a root StackLayout that has x:DataType set, and a child StackLayout that resets x:DataType to null, moving any of the Slider instances initially works but then they become unmovable (app hang on iOS, eventual crash on Android).

    <StackLayout x:DataType="local:HslColorViewModel">
        <StackLayout.BindingContext>
            <local:HslColorViewModel Color="Sienna" />
        </StackLayout.BindingContext>
        <BoxView Color="{Binding Color}"
                 VerticalOptions="FillAndExpand" />
        <StackLayout x:DataType="{x:Null}"
                     Margin="10, 0">
            <Label Text="{Binding Name}" />
            <Slider Value="{Binding Hue}" />
            <Label Text="{Binding Hue, StringFormat='Hue = {0:F2}'}" />
            <Slider Value="{Binding Saturation}" />
            <Label Text="{Binding Saturation, StringFormat='Saturation = {0:F2}'}" />
            <Slider Value="{Binding Luminosity}" />
            <Label Text="{Binding Luminosity, StringFormat='Luminosity = {0:F2}'}" />
        </StackLayout>
    </StackLayout>   

Steps to Reproduce

1. Run the attached sample.
2. Navigate to the MixedBindingsPage (final page in the ListView).
3. Move any of the sliders for a couple of seconds.

Expected Behavior

The BoxView color is updated as the sliders move, and the sliders can move indefinitely.

Actual Behavior

The BoxView color is updated as the sliders move, but after a couple of seconds it becomes impossible to move any of the sliders as the app has hung.

Basic Information

• Version with issue: 3.2.0.729530-pre2
• IDE:
• Platform Target Frameworks:
  • iOS: 11.4
  • Android: 8.1
  • UWP: Not tried.
• Android Support Library Version: 27.0.2

Reproduction Link

DataBindingDemos.zip