'ProcessContent' was not found in type 'PhoneApplicationPage'

[mesbahuk]

I have a Windows Phone Silverlight 8.1 app where I need to use XCC.
Two custom compilation symbols been added: RAW_APP & PRO_APP

My page's xaml:

<phone:PhoneApplicationPage
    ...
    xmlns:rawApp="condition:RAW_APP"
    xmlns:proApp="condition:PRO_APP"
    mc:Ignorable="d rawApp proApp"
    mc:ProcessContent="rawApp:* proApp:*"
    ...
>

Here my designer didn't complain, but when I ran my project, a XamlParseException occured:

Does XCC support Silverlight apps?