WindowsForms DockingManager doesn’t have direct support to set control in Document State as like setting Dock, AutoHidden or float state. 

Need to consider below functionalities with document window implementation

* Implement Document state with Tab 
* Provide option to create Horizontal/ Vertical Tabgroups. 
* Provide support to change the state of the Document window as like VS2010 (Drag the document and make as float). 
* Provide support to change any window into Document window by through Drag providers (Drop at center make window as Document). 
* Provide preview support while dragging the Document window. 
* Provide required events and properties for Document state. 
* Implement VisualStyles for DocumentContainer as like DockingManager. 
* Serialization support for Document windows tab groups.