Why is it not possible to add a CommandBarController to a form containing XP Menus and ToolBars in Windows Forms CommandBar (CommandBars)

The CommandBars Framework should be used only with the standard .NET Menus/ToolBars and not with the Essential Tools XP Menus. This is because the XP Menus designer infrastructure will freeze the .NET environment.

Menu with command bar

But it is possible to add a CommandBar to a form containing XP Menus through code as shown in the sample screenshot.