Make Buttons' Image properties of Object type.

Make the gallery resizable

Currently, Title and Description properties are typed to string and the control template uses TextBlock controls to display these properties, I think that only typing these properties to "object", showing them with  ContentPresenters and adding a pair of DataTemplate Dependency properties (TitleTemplate and DescriptionTemplate) would offer an extremely flexibility to this useful control.

Declined: If the users need to transfer object data to the ScreenTip they could use the Tag property(http://msdn.microsoft.com/en-us/library/system.windows.frameworkelement.tag%28v=vs.110%29.aspx)  and bind its value to an custom Implicit style targeting the ScreenTip. 

RibbonGroup collection can be populated only w/ buttons from the designer

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

When the DropDownButton in an ApplicationMenu is clicked, the DropDown area should not be closed (see MS Excel for reference).

Expose an IsActiveChanged event for the ContextualGroups

Will be available in Q1 2015 Release.

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.

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

ApplicationMenu do not have keyboard navigation - pressing arrows do not navigate thru the application menu items.
Declined as a duplicate of: https://feedback.telerik.com/wpf/1352753-ribbonview-applicationmenu-do-not-have-keyboard-navigation.

The constructor of the GroupVariantCollection is internal

Reason for declining: The RadRibbonGroup uses the GroupVariantCollection internally and as there is no public property of type GroupVariantCollection there is not need for the constructor to be exposed. Also if the users wants to bind the Variants of the RadRibbonGroups they can use the VariantsSource property which is of type IEnumebable<GroupVariant>.

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

Allow hiding the tab headers - when a single tab is displayed a tab header is not needed and it can be programmatically hidden in order to save space.

UPDATE: HeaderVisibility property can be used to achieve this behavior

Allow changing the entire UpDownButton tooltip.

We have RadRibbonView. There is some elements in a RadTab, that are inside RadOrderedWrapPanel.
If we set a theme to the RadRibbonView, it is not applied to the elements within the RadOrderedWrapPanel.

Reason for declining: The RadRibbonGroup propagate its theme to its direct children, all nested elements in RadOrderedWrapPanel or custom panel/grid e.t should have set their theme using the attached property telerik:StyleManager.Theme which will be bound to the same theme as the RadRibbonView.

Cite:
The problem is displaying ScreenTip for Application Button.
Move the mouse on Application Icon, no tooltip shows.
Click it to show the list of menus and go to the first item.
The ToolTip shows up under the menu.

Available in LIB version: 2014.3.1312

RibbonWindow throws a TypeInitializationException when used with VSTO Addin

It is impossible to prevent the application menu from closing.

Note:  The ApplicationMenuOpenStateChanged event of the RadRibbonView could be used to prevent closing of Application menu. This approach is demonstrated in the attached project.

In application Menu, when hovering the dropdownbutton to open the RightPane, clicking an item in the Pane does not closes the application menu

Implement DirectionalNavigation