Currently CDN + Styles combine is not possible. Let me explain:
The way local combine works is to first find all referenced stylesheets (which may vary on per page basis) and create a virtual combined file on the fly. Each unique combination has a unique virtual file.
Аpplying this to the CDN, it will be virtually impossible to have all possible combinations prepared and uploaded on the CDN. Not to mention that some of those combinations will be gigantic in size.
At the same time it will make a good feature to have a sort of "bundles" e.g. you are using the Default skin and you get the entire default skin in one neat file.
I have logged the feature in our Feedback Portal -- http://feedback.telerik.com/Project/108/Feedback/Details/47874-add-bundling-support-for-stylesheetmanager
-- for you and other customers to vote for and comment on.
the Telerik team
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