Issue in windows phone 8 : The attachable property 'RootVisual' was not found in type 'Application'

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Windows-Phone-8

Hi Everyone,

I have got few issues while trying to implement a sliding menu ("Facebook" like) in my windows phone 8 application.

When I added the following code in app.xaml, it shows following issues

<Application.RootVisual>
            <library:SlideApplicationFrame Header="ManageIT"
                                       Background="White">
                <!--<library:SlideApplicationFrame.LeftContent>
                <pages:LeftView />
            </library:SlideApplicationFrame.LeftContent>-->
                <!--<library:SlideApplicationFrame.RightContent>
                <pages:RightView />
            </library:SlideApplicationFrame.RightContent>-->
            </library:SlideApplicationFrame>
        </Application.RootVisual>

The exception is given below.

Error   1   Nested properties are not supported: Application.RootVisual.
Error   2   The attachable property 'RootVisual' was not found in type 'Application'.
Error   3   Unexpected PROPERTYELEMENT in parse rule PropertyElement ::= . PROPERTYELEMENT Content? ENDTAG..

Can anyone help me to solve this?
Is it because the reference to System.Windows.UIElement is not done?

Regards
Sebastian