We are not able to reproduce such a problem by using VS 2010 SP1 and opening either the minified or non-minified versions of the CSS files.
The problem might be caused by some CSS hacks, which crash the VS parsing mechanism, or something else related to the formatting of the files (line endings, etc), or a Visual Studio plugin. Let us know if you discover anything particular and we will take a look.
the Telerik team
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