How to create docking windows using the WinForms Docking Manager designer?
Create a docking window
1. Select the Essential Tools DockingManager component from the Windows Forms designer toolbox and drop it onto the design form.
2. The DockingManager is implemented as an extender provider and adds the SetEnableDocking() function to all controls that are direct children of the form.
3. Set the SetEnableDocking() function to True for those controls that need to be hosted as docking windows. Turning on this property will immediately transform the control into a docking window and adds certain other docking relevant extended properties to the control.
4. The form’s docking layout can now be set by simply dragging the controls around and docking them at the desired location. The docking windows designer automatically persists the form’s dock state and the persisted state is applied when the form is loaded.
Reference link: https://help.syncfusion.com/windowsforms/dockingmanager/dock-window