Tear-off MDI Child Windows
BCGControlBar Pro (MFC)
BCGControlBar for .NET
This feature is similar to Visual Studio, Internet Explorer or MS Edge tabbed documents: simply click the MDI tab and drag it outside the main application window. You will see a new frame with a single MDI document. You can add other MDI child windows to the newly created frame or return it back to the main application window by dragging MDI tab.
Important: this feature is available only if you enabled MDI tabbed groups.