Hi Andrey,
NewDockStateEndLoad event and Form Closing event is the better place to load and save the dock state respectively. Do you load your dock state in form load event? If yes, Please call the
LoadDockState method in the NewDockStateEndLoad event. This event will trigger after the form load event. Please take a look at the sample and let me know if this meets your requirement.
Thank you for using Syncfusion products.
Regards,
Vijay
Test Sample