In RadGridView, column header cells and their filter buttons are not exposed to UI Automation (UIA) clients.

Workaround: Subclass DataCellsPresenter, override OnCreateAutomationPeer() to return a custom peer that walks the visual tree for GridViewHeaderCell children and exposes their real peers. This subclass must be wired in via a retemplated GridViewHeaderRow (swap the DataCellsPresenter template part).

public class FixedDataCellsPresenterAutomationPeer : FrameworkElementAutomationPeer
{
    public FixedDataCellsPresenterAutomationPeer(FixedDataCellsPresenter owner)
        : base(owner)
    {
    }

    protected override List<AutomationPeer> GetChildrenCore()
    {
        var children = new List<AutomationPeer>();
        CollectHeaderCellPeers(this.Owner, children);
        return children;
    }

    protected override AutomationControlType GetAutomationControlTypeCore()
    {
        return AutomationControlType.Header;
    }

    private static void CollectHeaderCellPeers(DependencyObject parent, List<AutomationPeer> result)
    {
        int count = VisualTreeHelper.GetChildrenCount(parent);
        for (int i = 0; i < count; i++)
        {
            var child = VisualTreeHelper.GetChild(parent, i);
            if (child is GridViewHeaderCell headerCell)
            {
                var peer = UIElementAutomationPeer.CreatePeerForElement(headerCell);
                if (peer != null)
                {
                    result.Add(peer);
                }
            }
            else
            {
                CollectHeaderCellPeers(child, result);
            }
        }
    }
}

  public class FixedDataCellsPresenter : DataCellsPresenter
  {
      protected override AutomationPeer OnCreateAutomationPeer()
      {
          return new FixedDataCellsPresenterAutomationPeer(this);
      }
}

<Window.Resources>
    <ControlTemplate x:Key="FixedGridViewHeaderRowTemplate" TargetType="grid:GridViewHeaderRow">
          <!-- other elements -->
            <local:FixedDataCellsPresenter x:Name="PART_DataCellsPresenter"
                                           AutomationProperties.Name="Header Cells Presenter"
                                           Grid.Row="1"
                                           Grid.Column="3" />
           <!-- other elements -->
    </ControlTemplate>
    <Style TargetType="grid:GridViewHeaderRow">
        <Setter Property="Template" Value="{StaticResource FixedGridViewHeaderRowTemplate}" />
    </Style>
</Window.Resources>

Initially RibbonView gets rendered design-time. Trying to edit RibbonTab-s or add new one causes the whole control to dissapear in the designer. Clean and rebuild of the solution doesn't help -- cleaning the Shadow cache of Visual Studio Designer is the onliest thing that helps.

The issue reproduces with Class Library containing the Ribbon setup and IsWindowsThemeEnabled property of RibbonWIndow turned off (default value).

The issue is reproducible in Fluent theme as well.

When a RadDocking is located inside a RadTabControl and the RadPaneGroup contains only one RadPane the content is scrolled(if located inside a ScrollViewer)

When the main container of a window is ScrollViewer, the caret is not kept in the view while users move it with the arrow keys.

BindingExpressionError occurs in situations  when the tree is virtualized and TemplateSelectors are used

When the custom map provider supports levels range other than 1 to 20 then it could affect to tiles downloading performance.

System.Windows.Media.Animation Warning is apparent during DragDrop in the TreeView in WPF. 

When a System.Windows.Interactivity.EventTrigger is attached to a ChartTrackBallBehavior a XamlParseException is thrown. A possible work-around for this would be to set the CommandParameter to be the parent collection of the behavior and not the behavior itself.

If the RadSpreadsheet is declared as a child content in the RadBusyIndicator, there isn't any tab selected as active in the SheetSelector.

Workaround: Declare the busy indicator after the RadSpreadsheet not as its child.

For example, instead of:

<telerik:RadBusyIndicator>
    <telerik:RadSpreadsheet x:Name="radSpreadsheet" />
</telerik:RadBusyIndicator>

Do:

<Grid>
    <telerik:RadSpreadsheet x:Name="radSpreadsheet" />
    <telerik:RadBusyIndicator />
</Grid>

RibbonWindow icon appears clipped when the DPI  is set larger than 100%. Also, the icon separator is offset.

Workaround:
The issue is caused by the MajorTickInterval property, so one way to go is to remove this setting and use the LabelInterval instead. This will plot more ticks than before, but should eliminate the label clip. If the number of ticks bothers you, you can set the MajorTickLength property of the axis to 0 (so that the ticks are not visible) and use a LabelTemplate in which you will include a label and a tick. 

Another, simpler, work-around is to set a right margin of the chart and set the ClipToBounds property of the chart to false.

Cannot properly scroll when using StackPanel as ItemsPanel.

When you make the window very small in height and then revert it back to normal size the Pie connectors are gone.

When RadRichTextBox.DocumentInheritsDefaultStyleSettings is set to true, lists in the document are exported to HTML with Verdana font, instead of with the font applied in the UI.

Workaround: Use modification of the document default styles ("Normal") instead of setting DocumentInheritsDefaultStyleSettings  to true, e.g.:
this.radRichTextBox.Document.StyleRepository["Normal"].SpanProperties.FontFamily = new FontFamily("Segoe UI");

The AM/PM value is not shown in the cell when formatting a time value.

Steps to reproduce:
1. Insert some time in a cell in spreadsheet (22:20)
2. Apply it a custom format that contains AM/PM (e.g. "h:mm AM/PM")

Observed: The AM/PM format is missing
Expected: AM or PM should be shown after the time (image attached) 

Declined: The changes could be applied if the user presses OK button instead of pressing Enter key. A new feedback item is open where the issue is described: https://feedback.telerik.com/Project/143/Feedback/Details/212042-spreadsheet-custom-number-type-values-in-format-cells-dialog-are-not-applied-wh