We have a RadRibbonWindow.
When it is run on Windows XP (or on Windows 7, "Windows Classic" theme) and the DPI settings are high (above 170 %), the standard window buttons (Minimize, Restore and Close) are not displayed properly (they are cut). Also there is too much space between them.

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

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

Close command needed when using the close button

The command could be intersected as follow: 
 static MainWindow()
{
      RadRibbonWindow.IsWindowsThemeEnabled = false;
       CommandManager.RegisterClassCommandBinding(typeof(MainWindow), new CommandBinding(Telerik.Windows.Controls.RibbonView.Shell.SystemCommands.CloseWindowCommand, CloseWindowExecuted, canExecute));
}

Please note that this command is available only if RadRibbonWindow.IsWindowsThemeEnabled is set to "false".

Available in R1 2017 Release

When the Taskbar is auto-hidden, if the RibbonWindow is maximized, the task bar cannot be displayed.

RadRibbonDropDownButton DropDownIndicator isn't rotated when the DropDownButtonPosition is Right and the DropDownPlacement is Right

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

Add an way to include the Microsoft standard "Press F1 for help" to screentips in the ribbon, including the behavior to perform an action when the F1 key is pressed.

UPDATE: The RibbonView exposes a HelpCommand property which basically sets the Help button command. Additionally the Help button has a predefined ScreenTip which content is controlled by the “RibbonViewHelp” resource key. You can easily change the value returned by the ResourceManager for that resource key to change the default ScreenTip information.

As for performing a custom action on F1, this is considered application logic which can easily be implemented through InputBindings (http://msdn.microsoft.com/en-us/library/system.windows.uielement.inputbindings%28v=vs.110%29.aspx).

ActivatePreview event does not fire when the  gallery is databound

Available in Q1 2015 Release.