Hi Dima,
I am afraid, I was not able to see the issue in LoadDesignerDockState method. Could you please give me the Syncfusion Essential Studio version currently you are using? However I have created a test sample and attached with this response. Please take a look at the sample and let me know if this helps you. Otherwise Please modify this sample and send it over to me. It will help us to investigate the issue exactly.
Thanks for your interest in Syncfusion Products.
Regards,
Vijay
Sample