I am having the issue in version 11.1 2282.  The image below shows that the red area should be between the two thumbs.

Hello,

I have modified the sample project following your scenario and everything seems to work ok on my side. If the sample doesn’t satisfies all your needs feel free to modify it, so it reproduces your behavior and send it back to me for further investigation.

Looking forward for your reply.

This issue isn't resolved.  I tested on 2011.1 (2282) and 2011.2 and getting the same results.  In the following example, we have a simple slider with two thumbs.  If you drag the first thumb all the way to the right, it should push the right thumb as well.  The track fill gets an incorrect render by filling in the entire grid.  The same thing occurs when you move the right thumb all the way to the left.

<Grid Margin="20">

<StackPanel>

<TextBlock Text="Infragistics Numeric Range Slider:" Margin="0,10,0,0" />

<ig:XamNumericRangeSlider DecreaseButtonVisibility="Collapsed" IncreaseButtonVisibility="Collapsed">

<ig:XamSliderNumericThumb Value="10" TrackFillBrush="Transparent" InteractionMode="Push" />

<ig:XamSliderNumericThumb Value="50" InteractionMode="Push" />

</ig:XamNumericRangeSlider>

</StackPanel></Grid>

Hello,

I can suggest you define your Thumbs like this:

<Grid>
    <ig:XamNumericRangeSlider Name="xamNumericRangeSlider1" DecreaseButtonVisibility="Collapsed" IncreaseButtonVisibility="Collapsed">
        <ig:XamSliderNumericThumb Value="50" TrackFillBrush="Red" InteractionMode="Push" />
        <ig:XamSliderNumericThumb Value="10" TrackFillBrush="Transparent"  InteractionMode="Push"  />
    </ig:XamNumericRangeSlider>
</Grid>

Hope this helps you.

Hello,

I created a sample project for you following your scenario and everything seems to work ok on my side. If the sample doesn’t satisfies all your needs feel free to modify it, so it reproduces your behavior and send it back to me for further investigation.

Looking forward for your reply.

Thanks for the quick response.  The bug is still there.  If you push either thumb to the other side (left all the way to right or right all the way to left), both thumbs are pushed expected but has an incorrect fill when you move the thumb.  The selection brush should always be between the thumbs.  It looks like the thumbs is crossing over each other when you push them to either side of the slider and then swap their positions, which results in the incorrect rendering.