Investigations and fixes for the Foo

[mattleibow]

Description of Change

A test is failing:

System.NullReferenceException : Object reference not set to an instance of an object.
   at System.Runtime.CompilerServices.ConditionalWeakTable`2.Remove(TKey key)
   at Microsoft.Maui.Controls.Setter.UnApply(BindableObject target, Boolean fromStyle) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/Setter.cs:line 112
   at Microsoft.Maui.Controls.Style.UnApplyCore(BindableObject bindable, Style basedOn) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/Style.cs:line 167
   at Microsoft.Maui.Controls.Style.Microsoft.Maui.Controls.IStyle.UnApply(BindableObject bindable) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/Style.cs:line 109
   at Microsoft.Maui.Controls.MergedStyle.SetStyle(IStyle implicitStyle, IList`1 classStyles, IStyle style) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/MergedStyle.cs:line 187
   at Microsoft.Maui.Controls.MergedStyle.set_ImplicitStyle(IStyle value) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/MergedStyle.cs:line 93
   at Microsoft.Maui.Controls.MergedStyle.OnImplicitStyleChanged() in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/MergedStyle.cs:line 132
   at Microsoft.Maui.Controls.MergedStyle.<RegisterImplicitStyles>b__30_0(BindableObject bindable, Object oldvalue, Object newvalue) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/MergedStyle.cs:line 148
   at Microsoft.Maui.Controls.BindableObject.SetValueActual(BindableProperty property, BindablePropertyContext context, Object value, Boolean currentlyApplying, SetValueFlags attributes, Boolean silent) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/BindableObject.cs:line 537
   at Microsoft.Maui.Controls.BindableObject.SetValueCore(BindableProperty property, Object value, SetValueFlags attributes, SetValuePrivateFlags privateAttributes) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/BindableObject.cs:line 469
   at Microsoft.Maui.Controls.BindableObject.SetValueCore(BindableProperty property, Object value, SetValueFlags attributes) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/BindableObject.cs:line 401
   at Microsoft.Maui.Controls.Element.OnResourceChanged(BindableProperty property, Object value) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/Element.cs:line 745
   at Microsoft.Maui.Controls.Element.OnResourcesChanged(IEnumerable`1 values) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/Element.cs:line 601
   at Microsoft.Maui.Controls.Element.OnParentResourcesChanged(IEnumerable`1 values) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/Element.cs:line 553
   at Microsoft.Maui.Controls.VisualElement.OnParentResourcesChanged(IEnumerable`1 values) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/VisualElement.cs:line 1138
   at Microsoft.Maui.Controls.Element.OnParentResourcesChanged(Object sender, ResourcesChangedEventArgs e) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/Element.cs:line 548
   at Microsoft.Maui.Controls.Element.OnResourcesChanged(IEnumerable`1 values) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/Element.cs:line 579
   at Microsoft.Maui.Controls.Element.OnParentResourcesChanged(IEnumerable`1 values) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/Element.cs:line 553
   at Microsoft.Maui.Controls.VisualElement.OnParentResourcesChanged(IEnumerable`1 values) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/VisualElement.cs:line 1138
   at Microsoft.Maui.Controls.Element.OnParentResourcesChanged(Object sender, ResourcesChangedEventArgs e) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/Element.cs:line 548
   at Microsoft.Maui.Controls.Element.OnResourcesChanged(IEnumerable`1 values) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/Element.cs:line 579
   at Microsoft.Maui.Controls.Element.OnParentResourcesChanged(IEnumerable`1 values) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/Element.cs:line 553
   at Microsoft.Maui.Controls.VisualElement.OnParentResourcesChanged(IEnumerable`1 values) in /Users/builder/azdo/_work/2/s/src/Controls/src/Core/VisualElement.cs:line

[mattleibow]

Of course this is green...