Xamarin - slide element within Frame outside of view - xaml

Question

Not really sure how to properly describe my problem using correct wording as I'm new to Xamarin and Xaml.
I have a Frame with several StackLayouts within and I want to slide a specific StackLayout outside the Frame without showing it outside the Frame.
I can currently do this with:
XAML:
<ContentPage
xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:controls="clr-namespace:XLabs.Forms.Controls;assembly=XLabs.Forms"
xmlns:mr="clr-namespace:MR.Gestures;assembly=MR.Gestures"
x:Class="iRemote.UI.Maps.LocationFinderMap"
xmlns:map="clr-namespace:iRemote.Location"
Title="Location Finder">
<Frame HasShadow="true" OutlineColor="Color.Black" WidthRequest="700" HeightRequest="300" Padding="3"
BackgroundColor="White">
<mr:StackLayout x:Name="sl_main" Padding="2" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand"
Orientation="Horizontal" WidthRequest="200">
<StackLayout HorizontalOptions="Start" Orientation="Vertical">
<StackLayout HorizontalOptions="FillAndExpand" Orientation="Horizontal">
<Label Text="Parcel #" />
<Entry x:Name="txtParcel" WidthRequest="100" />
<Label HorizontalOptions="FillAndExpand" />
<Button x:Name="btnClose" BackgroundColor="#0786a3" BorderRadius="30" TextColor="White"
Text="Close" HorizontalOptions="End" />
</StackLayout>
<StackLayout HorizontalOptions="FillAndExpand" Orientation="Horizontal">
<Label Text="Meter #" />
<Entry x:Name="txtMeter" WidthRequest="100" />
</StackLayout>
<StackLayout HorizontalOptions="FillAndExpand" Orientation="Horizontal">
<SearchBar x:Name="search" Placeholder="Search" />
</StackLayout>
<StackLayout Padding="2" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand">
<StackLayout HorizontalOptions="FillAndExpand">
<mr:Image x:Name="img_map" Source="down" HeightRequest="19" WidthRequest="32" />
</StackLayout>
</StackLayout>
</StackLayout>
<StackLayout x:Name="sl_map" Padding="2" HorizontalOptions="FillAndExpand" HeightRequest="5"
VerticalOptions="FillAndExpand" IsVisible="true" WidthRequest="300">
<map:ExtendedMap
BackgroundColor="Blue"
x:Name="MP"
IsShowingUser="true"
MapType="Street" />
</StackLayout>
</mr:StackLayout>
</Frame>
</ContentPage>
Code-Behind:
if (panelShowing)
{
var rect = new Rectangle(this.Width - sl_map.Width, sl_map.Y, sl_map.Width, sl_map.Height);
sl_map.LayoutTo(rect, 250, Easing.CubicIn);
}
else
{
var rect = new Rectangle(this.Width + sl_map.Width - 40, sl_map.Y, sl_map.Width, sl_map.Height);
sl_map.LayoutTo(rect, 200, Easing.CubicOut);
}
However, sl_map simply just shows outside the frame. I want it to not be visible as it crosses the border of the frame. I hope that's clear enough. Again, sorry if I'm not using the correct terminology. I'm a WinForms guy.