Hi,
Thanks for your continued interest in Syncfusion product.
The tool box installer is used to add the Syncfusion controls to the toolbox of the Visual studio editor. Please navigate to Start --> All Programs --> Syncfusion --> Essential Studio 4.4.0.51 --> troubleshooting --> Reset visual studio toolbox to run the toolbox installer
Essential Diagram V5.1 has been fully refactored to make the product more stable and maintainable. Here I have attached the Migration document which will help you to migrate to v.5.1.
http://www.syncfusion.com/Support/user/uploads/Migration Document_5320b292.zipPlease let me now if you have any queries.
Regards,
Ramu