The Title of the RadRibbonWindow should be created from the Title and ApplicationName strings of the RibbonView automatically

Title bar (including the Contextual tab header) goes over the Window (MinMaxClose) Buttons

When the window is resized, the Title should transform to Shorter Text + "...." like in MS Officce (Word, Excell, etc.)

The title of the RadRibbonWindow can't be trimmed when resizing the window. Even the window's buttons are overlapped

The Title of the RadRibbonWindow is not diplayed unless there is a RadRibbonView in the window.

When the ItemTemplateSelector property is used the class which inherits the DataTemplateSelector is never called.

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".

The MinimizeButton of the RadRibbonView have mismatched states(When the ribbon is collapsed the arrow should be pointing Up, and when the ribbon is collapsed should be pointing Down) not the other way around

If a RibbonView with Backstage menu is hosted in a RibbonWindow and the window's MinWidth and MinHeight properties are applied, when the Backstage is opened the size restrictions are no longer respected.