MasterDetailPage not scrollable when orientation change

Hi,

Here is my problem, if my listview items didn't exceed screen size to enable scrolling in portrait mode, then when rotate to landscape mode, not everything fits on the screen now, which the scrolling should be enabled but didn't.

however if you change a view like go to a modal window and come back to the list, it will work as it should. It seems to me that on rotation the listview height didn't get updated to enable scrolling in landscape mode. Is this a bug?

Below is my code, any suggestions I can improve on this?

thanks,

    <MasterDetailPage.Master>
        <ContentPage x:Name="slideout" StyleId="slideout" Title="Menu" Icon="slideout.png">
            <StackLayout BackgroundColor="{l:GlobalResource DarkBackground}">
                <ContentView Padding="10,36,0,5" BackgroundColor="{l:GlobalResource DarkBackground}">
                        <Label Text="MENU" Font="Medium" TextColor="{l:GlobalResource LightestText}"/>
                </ContentView>
                <ListView BackgroundColor="{l:GlobalResource DarkBackground}" StyleId="menu" x:Name="Menu" ItemTapped="MenuClicked">
                        <ListView.ItemTemplate>
                        <DataTemplate>
                                         ..........
                        </DataTemplate>
                        </ListView.ItemTemplate>
                </ListView>
            </StackLayout>
        </ContentPage>
</MasterDetailPage.Master>