The current workaround we can offer is to define the following style for the RadioButton element:

			<Style TargetType="RadioButton" BasedOn="{StaticResource RadioButtonStyle}">
				<Style.Triggers>
					<Trigger Property="IsChecked" Value="True">
						<Setter Property="BorderBrush" Value="{telerik1:FluentResource ResourceKey=AccentBrush}" />
					</Trigger>
				</Style.Triggers>
			</Style>

Where 
        xmlns:telerik1="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls"

Custom property values for BorderThickness and BorderBrush are replaced after button click.

To reproduce, use the following code, you'll see that a highlighted border appears after clicking the button.

<telerik:RadButton Background="Gray"
                           Foreground="White"
                           BorderThickness="0"
                           BorderBrush="Transparent"
                           Content="click me"
                           HorizontalAlignment="Center"
                           VerticalAlignment="Center" />

Reason for declination: 
The border that you see is the focused state of RadButton, which is a separate visual and its BorderThickness is not template-bound to the BorderThickness of the control intentionally. We believe that a control should have focus even if its default border is removed. In our latest themes we are trying to keep this behavior. In the Office2016 theme there is an exposed palette property, which you can use in code-behind if you want to remove the focus: 
Office2016Palette.Palette.FocusThickness = new Thickness(0);

A StackOverflowException occurs when you press a RadDropDownButton placed into the DropDownContent of another RadDropButton.

To work this around, subscribe for the LostMouseCapture event of the parent drop down button and handle it.

private void DropDownButton_LostMouseCapture(object sender, MouseEventArgs e)
{
      e.Handled = true;
}

The UI freezes if the DropDownContent of RadDropDownButton has a native Run element and the CloseOnPopupMouseLeftButtonUp property is set to True.

If you have a tooltip on a button and focus the button before hovering it, the tooltip is not shown

Implement mechanism that allows positioning the drop down content of RadDropDownButton when the DropDownPlacement property is set to Absolute or Relative. Something like DropDownHorizontalOffset and DropDownVerticalOffset.

It should be possible to specify whether the drop down should stretch to the width of the button or whether it should be left - right aligned. The same should apply for the vertical positioning when the popup appears left or right of the button.

There is a Dispatcher call without checking in the dispatcher call for NULL. This lead to NullReferenceException in huge production code.



Available in R3 2016 SP

MouseLeave event is never fired after we change the Them of the controls from a control located in the DropDownContent. Therefor the controls IsMouseOver property is true and looks like it is hovered.

The issue is not reproducible since R2 2016 SP1 version.

In that way it will be easy to set the popup animation to be slide, fade or scroll without setting a custom template. 

Available in R1 2017 Release

Clicking on the RadSplitButton in XAML opens the designer unexpectedly

Available in LIB version: 2015.1.0309

DropDownButton's DropDownContent blinks when its template and its parent's ControlTemplate are changed at runtime

The issue can be reproduced with DatePicker inside of ComboBoxItem ItemTemplate.

Available in LIB Version 2016.3.1010, it will be also available in the 2016 R3 SP1.

Property values are inherited from the logical parent and not visual parent (as in SL). Thus ContentPresenter and ContentControls children doesn't get the new Foreground property. This can not be workarounded with VisualStates, but Triggers only

Reason for declination: WPF limitation

Add a visual representation for the IsDefault property like in Microsoft's button.

The native radio button supports validation. Implement validation for the RadRadioButton

Arg_COMException in some cases when used with RoutedUICommand

SplitButton throws a design time exception with implicit styles if you've included Diagrams.Extensions.xaml

Update the Buttons AutomationPeer to use the AutomationProperties attached properties.

As a workaround you can create a custom button control deriving from RadButton. That would allow you to create a custom AutomationPeer class that can return the AutmationProperties.Name value to a narrator application