The gauge control will have new knob-like indicator.

When the gauge contains a scale which is interactive (IsInteractive property is true) and when the Gauge control it is embed inside the RadFluidContentControl.LargeContent then it throws an exception.  ComException with Message: UCEERR_RENDERTHREADFAILURE.

This is reproducible also:
- In any control that uses animation transitions to change its content. 
- If many instances of a gauge control are added in the transition's control content.

It should be possible to specify origin of the bar indicator. For example, the radial scale is going from -10 to 10. In the current implementation bar indicator always starts at the minimum of the scale. We should have an ability to change origin of the bar indicator so that it starts at 0. I.e. if the value of the bar indicator was set to 5 then the bar should start at 0 and go to 5, currently is starts at -10 and goes to 5.

BarIndicator is not updated when using GaugeRanges and their Min and Max properties are changed at runtime. The indicator's layout is updated only when the gauge control is re-sized.

Possible workaround:

Update measure and arrange the  BarIndicator control manually. 

        var size = this.BarIndicatorRanges1.RenderSize;
        this.BarIndicatorRanges1.Measure(Size.Empty);
        this.BarIndicatorRanges1.Measure(size);
 
        this.BarIndicatorRanges1.Arrange(new Rect(size));
        this.BarIndicatorRanges1.UpdateLayout();

When the Ranges property of scale is bound inside a user control then it causes the "Object reference not set to an instance of an object" exception in the Telerik.Windows.Controls.Gauge.ScaleBase.OnApplyTemplate method.

As a workaround you can set the Ranges property to empty GaugeRangeCollection in your user control using the SetCurrentValue method which does not break the databinding. Also it will require to set the Ranges.ItemTemplate property after the scale is loaded.

The Visibility property of GaugeRange is not applied when it is set or bound in xaml

As a workaround if you set the Visibility in code after the range is loaded, the property's value is applied correctly.

As a workaround you need to use a ProportionalBrush mode instead.

When the Effect property of the gauge's scale is set (to BlurEffect for example) any mouse interaction with the control is lost. 

If the Effect property of the panel that wraps the gauge is set, the mouse interaction of all children of this panel is lost.

Workaround:
Disable the interaction with the scale and implement the moving of the indicators on MouseLeftButtonDown. Here is an example:

<telerik:RadRadialGauge MouseLeftButtonDown="RadRadialGauge_MouseLeftButtonDown" >
    <telerik:RadialScal Min="1" Max="12" IsInteractive="False">                
        <telerik:RadialScale.Indicators>
            <telerik:Needle />
            <telerik:Pinpoint />
        </telerik:RadialScale.Indicators>
    </telerik:RadialScale>
</telerik:RadRadialGauge>

Note that the IsInteractive property's default value is False so you can just skip setting it.
private void RadRadialGauge_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
    var mousePosition = e.GetPosition(this.rs1);
 
    double value = this.rs1.GetValueByPoint(mousePosition);
    foreach (UIElement element in this.rs1.Indicators)
    {
        InteractiveIndicator indicator = element as InteractiveIndicator;
        if (indicator != null)
        {
            indicator.Value = value;
        }
    }
}

One way to work around this is to include a dummy resource with the name of "HexagonalSevenSegsN"
<telerik:RadVerticalLinearGauge>
 <FrameworkElement.Resources>
  <DataTemplate x:Key="HexagonalSevenSegsN" />

The same exception is also thrown when you are trying to bind the NumericIndicator Value property when using SevenSegsNumberPosition position. In this scenario, the data context is not propagated to the NumericIndicator. To workaround this you can set the Source binding.
<Window.Resources>
     <local:TestViewModel x:Key="viewModel"/>
</Window.Resources>

<tk:RadRadialGauge Name="gauge" Height="200" Width="200" Margin="5">
            <tk:RadialScale Min="0" Max="300" MajorTicks="10" LabelRotationMode="None">
                <tk:RadialScale.Indicators>
                    <tk:NumericIndicator  x:Name="numericIndicator" Value="{Binding TestValue,Source={StaticResource viewModel}}"

*** The fix for this issue will be available with the next LIB (version 2018.3.1217) expected on Monday, December 17.

When you resize (but only decreasing size) the control, the position and size of the Marker indicator is not updated. 

This is reproducible with RadVerticalLinearGauge and VerticalLinearScale. When the RelativeHeight of the scale is set to 1 and the RelativeY is set to 0.

As a work around you can avoid setting the RelativeHeight and RelativeY properties of VerticalLinearScale.

Indicators are clipped in some scenarios when the IsInteractive property of the VerticalLinearScale is True. 

Currently, when you use a logarithmic distribution for the gauge scale, the minor/middle ticks are positioned at equal spaces from one another. Add an API that allows you to position the minor/middle ticks using non exponential step. 

When the properties are bound in code behind, they are not updated as they are supposed to.

Binding them in XAML, by setting the DataContext of the control as StaticResource, works as expected.

If the numeric indicator is visualized on a large area (its container has large size), its segments are overlapping.

RangeList and TickList should support ability to set list of the arbitrary objects as ItemsSource and use ItemTemplate to create ranges and custom tick marks.

The visual elements generated for the GaugeRange objects are not cleared when you clear the Ranges collection of the scale. This happens if you call the Clear() method of the Ranges collection.

To work this around you can clear the ranges using the Remove() method instead of clear.

while (scale.Ranges.Count > 0)
{
    scale.Ranges.Remove(scale.Ranges.LastOrDefault());
}

When the Min and Max properties of the GaugeRange control are updated dynamically, a memory leak occurs, where ObjectRangeInfo elements are created but not released at a later time.
The fix is available in LIB Version 2015.2.803.

Currently, when you serialize a gauge control (using the XamlWriter.Save() method), the values of the properties of type GaugeMeasure are not serialized properly. Instead of the measure value, the result from the ToString() method of the GaugeMeasure() class is serialized - Telerik.Windows.Controls.Gauge.GaugeMeasure.

The decimal separator of a NumericIndicator should be visualized between the digits. At the moment it  takes one position.