Hello Deepak Shakya,
We were unable to reproduce such issue in the RadTabControl from Q2 or Q3 2011. The Style of the RadTabItem is successfully extracted from Blend. You can examine this in the attached solution. Please note that if once you have extracted a style, then made some changes to it, then extract the same style again, it may not be completed. Please let us know if this helped you or not.
All the best,
the Telerik team
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