Hi Andreas,
The problem with docking seven controls isn''t a limitation of DockingManager, as much as it''s a limitation of Form size. Eventually DockingManager runs out of room to dock controls and is forced to make them small. Shrinking your controls to the desired size as you add them can help avoid this problem.
To hide and show Controls, you should use SetDockVisibility. This prevents you from having to worry about serialization and load times. You can prevent the flicker this causes by using a hard lock on window painting.
I have attached a sample that demonstrates these things:
f29222_7HidableDockingWindows_1318.zip
Please take a look at it and let me know if you have any questions.
Regards,
Gregory Austin
Syncfusion Inc.