AbsoluteLayout doesnt align controls as expected when positions are same - xamarin.forms

Question

I am trying to get the similar popup as below on Androd, see the X close button is nicely lays on top of the frame. I copied code from the github to test but actual code is also not working. half of the button is always behind the frame. I thought that first added control goes below and 2nd one comes above if their position lays on each other. is there any exception here? whatever I tried i couldnt set button obove the frame. Can somebody sheds some light on usage of absolutelayout here?
<ScrollView
HorizontalOptions="Center"
VerticalOptions="Center">
<AbsoluteLayout>
<Frame
x:Name="FrameContainer"
Margin="15"
HorizontalOptions="Center"
BackgroundColor="White">
<StackLayout
IsClippedToBounds="True"
Padding="10, 5"
Spacing="3">
<Image
HorizontalOptions="Center"
x:Name="OctocatImage"
Margin="10"
HeightRequest="150"
WidthRequest="150">
<Image.Source>
<OnPlatform
x:TypeArguments="ImageSource"
Android="github_octocat.png"
iOS="github_octocat.png"
WinPhone="Assets/github_octocat.png"/>
</Image.Source>
</Image>
<Entry
HorizontalOptions="Center"
x:Name="UsernameEntry"
Style="{StaticResource EntryStyle}"
Placeholder="Username" />
<Entry
HorizontalOptions="Center"
x:Name="PasswordEntry"
Style="{StaticResource EntryStyle}"
Placeholder="Password"
IsPassword="True"/>
<Button
Margin="10, 5"
BackgroundColor="#7dbbe6"
HorizontalOptions="Fill"
Clicked="OnLogin"
x:Name="LoginButton"
Text="Login">
<Button.HeightRequest>
<OnPlatform x:TypeArguments="x:Double" Android="50" iOS="30" WinPhone="30"/>
</Button.HeightRequest>
</Button>
</StackLayout>
</Frame>
<ContentView
AbsoluteLayout.LayoutFlags="PositionProportional"
AbsoluteLayout.LayoutBounds="1, 0, -1, -1">
<ContentView.GestureRecognizers>
<TapGestureRecognizer Tapped="OnCloseButtonTapped"/>
</ContentView.GestureRecognizers>
<Image
x:Name="CloseImage"
HeightRequest="30"
WidthRequest="30">
<Image.Source>
<OnPlatform
x:TypeArguments="ImageSource"
Android="close_circle_button.png"
iOS="close_circle_button.png"
WinPhone="Assets/close_circle_button.png"/>
</Image.Source>
</Image>
</ContentView>
</AbsoluteLayout>
</ScrollView>
I just tried with a fresh project and below is how it looks like for me. Close button is always behind the frame. here you can find repro test project

Answer 1

Removed Frame and moved some attributes onto StackLayout. Related bug
https://bugzilla.xamarin.com/show_bug.cgi?id=55744
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:local="clr-namespace:test"
x:Class="test.MainPage">
<ContentPage.Resources>
<ResourceDictionary>
<Style x:Key="EntryStyle" TargetType="Entry">
<Setter Property="PlaceholderColor" Value="#9cdaf1"/>
<Setter Property="TextColor" Value="#7dbbe6"/>
</Style>
</ResourceDictionary>
</ContentPage.Resources>
<ContentPage.Content>
<ScrollView
HorizontalOptions="Center"
VerticalOptions="Center">
<AbsoluteLayout>
<StackLayout Margin="15" BackgroundColor="White"
IsClippedToBounds="True"
Padding="10, 5"
Spacing="3">
<Image
HorizontalOptions="Center"
x:Name="OctocatImage"
Margin="10"
HeightRequest="150"
WidthRequest="150">
<Image.Source>
<OnPlatform
x:TypeArguments="ImageSource"
Android="icon.png"
/>
</Image.Source>
</Image>
<Entry
HorizontalOptions="Center"
x:Name="UsernameEntry"
Style="{StaticResource EntryStyle}"
Placeholder="Username" />
<Entry
HorizontalOptions="Center"
x:Name="PasswordEntry"
Style="{StaticResource EntryStyle}"
Placeholder="Password"
IsPassword="True"/>
<Button
Margin="10, 5"
BackgroundColor="#7dbbe6"
HorizontalOptions="Fill"
x:Name="LoginButton"
Text="Login">
<Button.HeightRequest>
<OnPlatform x:TypeArguments="x:Double" Android="50" iOS="30" WinPhone="30"/>
</Button.HeightRequest>
</Button>
</StackLayout>
<ContentView
AbsoluteLayout.LayoutFlags="PositionProportional"
AbsoluteLayout.LayoutBounds="1, 0, -1, -1">
<Image
x:Name="CloseImage"
HeightRequest="30"
WidthRequest="30">
<Image.Source>
<OnPlatform
x:TypeArguments="ImageSource"
Android="close_circle_button.png"
/>
</Image.Source>
</Image>
</ContentView>
</AbsoluteLayout>
</ScrollView>
</ContentPage.Content>
</ContentPage>

Answer 2

It's a bug, set HasShadow="False" on your Frame and it should work.