Hi Johan_Stork,

You need only Telerik.Web.UI.dll, e.g. a reference to that assembly should be enough.

Best wishes,
Valeri Hristov (Senior Developer, MCSD)
the Telerik team

Ok, found it.

Do you have a Help. chm file for the Prometheus RadDock. The one that I downloaded is corrupt.

I also get some error when trying to add Telerik.Web.Ui to VS toolbox:

It needs assembly System.web.Extensions

What are these?

Hello Johan_Stork,

Could you try to download the CHM file again? I will inform our web team to check the file on the server and it if is corrupt, they will update it ASAP. Meanwhile, you could use our online help for reference:
http://www.telerik.com/help/radcontrols/prometheus/

System.Web.Extensions is the assembly of ASP.NET AJAX, which could be downloaded from:
http://www.asp.net/AJAX/

I strongly recommend reading the following help topics after you install ASP.NET AJAX:
http://www.telerik.com/help/radcontrols/prometheus/?GeneralASPNETAJAXInfo.html 
http://www.telerik.com/help/radcontrols/prometheus/?Adding%20RadControls%20Prometheus%20to%20an%20existing%20application.html
and
http://www.telerik.com/help/radcontrols/prometheus/?Troubleshooting.html

Please, let me know if you need additional information.

Greetings,
Valeri Hristov (Senior Developer, MCSD)
the Telerik team