When IsTabStop = False the focus is going through :

 *  RadAutoCompleteBox
 *  RadComboBox (when IsEditable is set to True)
 *  RadNumericUpDown
 *  RadMaskedTextInput
 *  RadDatePicker
 *  RadDateTimePicker

Available in the R3 2016 Release.

For RadAutoCompletebox, RadComboBox, RadDateTimePicker and RadNumericUpDown, the TabNavigationExtensions.IsTabStop attached property should be used to indicate whether the control is included in the tab navigation cycle.

For RadMaskedTextInput, MaskedInputExtensions.IsEditorTabStop attached property should be used.

It would be nice the DCTDecode filter to handle correctly images that are encoded in CMYK colorspace.

Currently, when a tool is executed it is invoked again after commit. The tool cannot be canceled from sequential execution.

Annotations are not positioned correctly, when the vertical scrollbar is visible.

The fix is available in LIB Version 2014.3.1319.

Exception is thrown if the size of Fluid is 0 and you maximize the window.

SelectedCells collection is not updated correctly after GridView's ItemsSource changed

Compress/decompress of specific file using streams can be wrong when the compression level is specified to Deflated.

The RibbonView TabStrip ScrollViewer is displayed unexpectedly when there are inactive ContextualGroups.

Problem noticeable by observing growth in queued changes to be processed. 

Available in LIB version 2018.1.205, it will be also available in the R1 2018 SP2 Release.

Missing StaticResource error (ScrollBarStyle) is thrown when using implicit styles and merging the Telerik.Windows.Controls.RichTextBoxUI.xaml file.

Silverlight uses short types internally for shapes' sizes and when the size of the line grows up to more than the short's max, extra lines are rendered. A possible work-around is to limit the zoom. 

When RowStyle is applied to RadGridView, AlwaysVisibleRow part disappears after adding a new item.  The problem occurs only when the style is applied explicitly. 

When the RadRibbonView ItemsSource is populated with RadRibbonTabs and one of the tab items IsSelected property is set to True that item no longer can be selected.

When the groups of a RadRibbonTab are collapsible the scroll is shown just before the groups collapses.