I'm using Expression Blend designer for UI work and I'm having hard time to get it working with v11.2. Basically the XamNumericRangeSlider works fine but it doesn't like when I add Thumbs and/or TickMarks in XAML.

So if I try to use something like this:

<ig:XamNumericRangeSlider IsSelectionRangeEnabled="True" MinValue="-10" MaxValue="10">
	<ig:XamSliderNumericThumb InteractionMode="Lock" Value="-5" />	
	<ig:XamSliderNumericThumb InteractionMode="Push" Value="0" />	
	<ig:XamSliderNumericThumb InteractionMode="Push" Value="4" />	
	<ig:XamSliderNumericThumb InteractionMode="Lock" Value="8" />	

	<ig:XamNumericRangeSlider.TickMarks>
		<ig:SliderTickMarks TickMarksFrequency="5" UseFrequency="True" />
	</ig:XamNumericRangeSlider.TickMarks>
</ig:XamNumericRangeSlider>

This doesn't work and the designer says "Cannot add content to an object of type "XamNumericRangeSlider" and from the TickMarks the error is "The member "TickMarks" is not recoqnized or is not accessible."

I think I've seen you using the previous markup in your samples and it works fine during runtime. It's just the designer that breaks. Should I add some references or XAML namespaces? the ig is mapped to xmlns:ig="http://schemas.infragistics.com/xaml" 

Am I trying to use it incorrectly? How could I get it working? It would make my life a lot easier to be able to work with the Blend Designer.