Hi Frederik,
Thanks for the update.
Please refer the sample below in which I have set focus to the textbox in the panel using ActivateControl method. I was not able to see that the focus is lost.
http://files.syncfusion.com/support/Tools.Windows/7.1.0.30/F80086/Tools_WF_Docking_Focus.zipPlease provide me more details if I misunderstood this.
Regards,
Jaya