Row-center directive not working on Surface simulator

Greetings,

It seems the row-center directive isn't working when building a Cordova app for the "windows" (i.e. Universal) platform. I'm using the following code in a Visual Studio Cordova project. It correctly centers the content vertically on Android (both Ripple emulator and VS emulator) but in the Windows AnyCPU simulator the text is at the top of the screen. {{windowHeight}} is bound to window.innerHeight.

<div class="row row-center">
    <div class="col col-33" style="height:{{windowHeight}}px"></div>
    <div class="col col-33"><p>Test content</p></div>
    <div class="col col-33" style="height:{{windowHeight}}px"></div>
</div>

Does anyone know how to vertically center content on Windows in this situation?

Thanks,
Jeff