RadControls for ASP.NET AJAX
Up to Q2 2011 SP1 the built-in skins were located in the Telerik.Web.UI.dll assembly.
Since Q3 2011 the Built-in skins are located in the
Telerik.Web.UI.Skins.dll assembly. The only exception is the Default skin which is still in
the Telerik.Web.UI.dll assembly.
The new assembly was introduced in Q2 2011 with four new skins being placed directly in it to show the path we are taking.
More information on this is available in
this blog post from the summer and in
this one from just after the Q3 release
This is done so that the skin usage is more intuitive - it allows us to separate the control functionality and the visual appearance.
Another advantage is that the main assembly size is reduced since it no longer contains images and stylesheets.
The new Telerik.Web.UI.Skins.dll assembly also has a version number that needs to match the version number of the main assembly in order to work.
Additional assembly registrations are not needed for it to work, if the correct Skins.dll is referenced in the project the RadControls
will find their skins.
This means that if you are using a skin different than the Default you need to include the Skins assembly in your project
(either in the GAC, or in the Bin folder).