XAML not rendering when using Windows phone toolkit -

i developing application. downloaded windows phone toolkit using phonetextbox. when try create phone text box control, control not rendering in xaml designer. running in emulator or phone. using visual studio 2013 community edition

what might problem?

for use windows phone toolkit, should add in following code in tags

<phone:phoneapplicationpage xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" ... xmlns:toolkit="clr-namespace:microsoft.phone.controls;assembly=microsoft.phone.controls.toolkit" ...