Currently, the minimized content of the ribbon opens up in a Popup element which leads to issues when positioned between two (or more) monitors. Introduce a feature that allows the content to opens in an Adorner element. 

Setting the KeyTipService.AltAccessText attached property on a RadRibbonGroup element should display a keytip on the dialog launcher of the group, when the keytips are activated.

Currently, if the group is collapsed, you can expand it using its AccessText. However, in this case the keytip of the dialog launcher is not displayed.

To work this around, subscribe to the Loaded event of RadRibbonGroup and set the KeyyTipService.AccessText property directly to the RadRibbonButton representing the dialog launcher.

private void RadRibbonGroup_Loaded(object sender, RoutedEventArgs e)
{
	var group = (RadRibbonGroup)sender;
	var button = group.ChildrenOfType<RadRibbonButton>().FirstOrDefault(x => x.Name == "DialogLauncher");
	if (button != null)
	{
		KeyTipService.SetAccessText(button, "D");
	}
}

Implement keyboard navigation for the items in the ApplicationMenu - through arrow keys for example.

Workaround:
In the Loaded event of the RibbonWindow, use the Telerik.Windows.Controls.RibbonView.Shell.WindowChrome class to get the current window and set its ResizeBorderThickness property to 0. 

public MainWindow()
{
    InitializeComponent();
    this.Loaded += MainWindow_Loaded;
}
 
void MainWindow_Loaded(object sender, RoutedEventArgs e)
{
    Telerik.Windows.Controls.RibbonView.Shell.WindowChrome chome = Telerik.Windows.Controls.RibbonView.Shell.WindowChrome.GetWindowChrome(this);
    chome.ResizeBorderThickness = new Thickness(0);
}

1. When the RibbonWindow is maximized the draggable area ends below the WindowTitle

2. In Normal state - the draggable area could be expanded in Material, Fluent and Crystal themes

A possible workaround is to change the WindowCaptionHeight property:

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