Hi Edwin,
I am afraid that I am not able to reproduce the issue of Screen.PrimaryScreen.WorkingArea not working as expected when the WindowState of the RibbonForm is set to Normal.
Could you please modify the attached sample so that the issue could be seen clearly? Also please let me know whether I have understood your requirement correctly. This will help us to resolve the issue soon.
http://websamples.syncfusion.com/samples/Tools.Windows/F63502/Main.htmWe appreciate your interest in Syncfusion products.
Best regards,
Golda