There are two issues with the demo:
1) The vertical tabstrip does not have width set
2) The container is not always wide enough to accumulate the tab and the multi page
So for the release we made it so to fix the width of the tabstrip when in vertical mode and we tweaked the width of the container so both the tabstrip and multipage fit.
(the latter issue is related to how IE10 renders pages when compared to other browsers)
the Telerik team
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