Implicit style doesn't apply on RadRibbonTabs which are added via PRISM.

UPDATE: An implicit style can not be applied on derived controls as their TargetType is different than the one defined in the implicit style. Basically if you set the style implicitly, the style is applied only on the types that match the TargetType exactly and not on elements derived from the TargetType value. You can find more information on the topic in the remarks section of the Style property definition: http://msdn.microsoft.com/en-us/library/system.windows.style%28VS.95%29.aspx

This is why in order to apply a Telerik predefined style on a UserControl deriving from RadRibbonTab, you  need to add a Style targeting the UserControl type in the Resources of the application. It is best to define that style after merging the Telerik ResourseDictionaries so that you can base the UserControl Style on the predefined "RadRibbonTabStyle".

If you delay adding a RibbonView in a RibbonWindow, the RibbonView is placed on top of the window, hiding its TitleBar.

When both Command and IsEnabled of RadRibbonBackstage are bound, the Command has Higher priority. This is inconsistency with the behavior of Buttons and RadButtons. The RadRibbonBackStageItems should work like RadButtons.

The KeyTips of RadMenuItems go behind the menu when hovering over the RadMenuItem. This issue seems to be related to the ScreenTip/ToolTip settings applied on the RadMenuItems - if no such settings are applied, the issue cannot be reproduced.
The Tooltip popup is placed over the KeyTips popup.

When a style is applied on the QAT, changing its position opens its popup menu unexpectedly. The style doesn't have to be customized, the issue is reproducable with the default OfficeBlack style of the control.

Currently the Backstage support keyboard navigation only if the the RadBackstageItems have their IsSelectable property set to true. The keyboard support should be extended to support BackstageItems that have IsSelectable=false.

Will be available in Q2 2015 Release.

When RoutedCommand is used in RadRibbonBackasteItem the OriginalSource is wrong.

RibbonGroup containes many TextBoxes with TabIndices set. HyperLink with TextBlock inside is between the TextBoxes. TextBlock Text is "" or x:Null.
Tabbing is possible only between the TextBoxes on the left of the Hyperlink.

The MinimizedPopup should be closed after clicking on a RibbonControl in the RibbonGroups

VS Designer trows exceptions if a RibbonTab is placed in a UserControl:  

If the RibbonTab control size isn't defined, the designer throws a System.InvalidOperationException - FrameworkElement_LayoutMeasure_InfinityNaNReturned.  

If the RibbonTab size is set, then clicking on the tab in the designer raises a System.ArgumentException - Property 'Items' was not found in the property collection 'Grid'. 

Currently only the Left Key activates the key tips.

The RibbonTabStrip does not collapse when Application Button is Collaps as well as the RibbonTabs.
This works in RibbonBar.

Available in LIB version: 2014.3.1402

RadGallery is used in RadRibbonView  and ListBox under the RibbonView with  DeferredScrollingEnabled set to true. When scrolling the Gallery, the ListBox Scrolls unexpectedly.

System.InvalidOperationException is thrown in the VS designer in a view defining a RadRibbontab control.

When you click on a control in the DropDownContent of a RibbonSplitButton, a click is registered in the underlying control (behind the DropDownContent).

When Windows Classic theme is applied in Windows7 ( or when XP is used) and the WindowStyle of the RadRibbonWindow is set to SingleBorderWindow, the scrollviewer in the backstage does not work properly

ElementName binding is not working in RadRibbonBackstage.

Reason for closing: The ElementName binding in Adorner is not supported and as the RadRibbonBackstage is Adorner it is not working there as well. Due to that framework limitation we cannot fix this issue and we will change the status of the feed back item to declined. You can find more information about the Adorner and its limitation in this article ( http://msdn.microsoft.com/en-us/library/ms743737%28v=vs.110%29.aspx ).

Edited Style of the ScreenTip does not apply when the ScreenTip is set as attached property.
Also, when you create a CustomControl deriving from the ScreenTip control, its default style is not applied.

I assume that even though this is listed under RadControls for Silverlight it will also apply to RadControls for WPF.

The ScreenTip isn't displayed unless you define its Title property